This test is designed to model 'real-world' performance of lossless data compressors. The test set contains a mix of different file types which are chosen with 'What do people use archivers for the most' in mind. The testset should contain data, weighted (in both type and proportion of files in the set) by how often these files are used for compression by normal users using compression software. So for example there will be more txt files then .ocx files in the set (yes, this is arbitrary). The set contains 100's of files and has a total size of over 300 Mb. The idea of a large collection is filtering out the 'noise'. A compressor might perform bad on 1 or 2 filetypes, but on a very large collection it will not hurt as much.

Some programs like CCM and BZIP2 can only compress one file at a time. For these programs a single TAR-file is created containing all files. The files in this TAR-file are ordered alphabetically on suffix, then name. Results of these compressors are marked with an 'Y' in the tarred column.

The testset consists of the following file types :

Considering the fact it's supposed to be a 'real-world' test I will not look at the best possible (command-line or gui) switch combination to use for optimal compression, but only test a limited set as 'normal users' would do. For 7-zip this means for example I will use the GUI and select the Ultra compression method (which can be easily beaten with some good command line switches), WinRar will be tested with max dictionary size and solid archiving etc. Programs are allowed to use a maximum of 800 Mb memory and must finish the compression stage within 24h. Compressed size must be 50% or less compared to the original size to be listed on MFC.

For my single file tests I got lots of requests to add the compression time to the tables. I did not do this for the reasons stated in the single file summary file, but I'm planning to measure compression times for this multiple file test!. I also decided to make this testset 'non public', so it's harder for developers to tune their program towards this specific test. I think this is the most fair way to get 'real life' performance tests.

Scoring system: The program yielding the lowest compressed size is considered the best program. The most efficient (read:use full) program is calculated by multiplying the compression time (in seconds) it took to produce the archive with the power of the archive size divided by the lowest measured archive size. The lower score the better. The basic idea is a compressor X has the same efficiency as compressor Y if X can compress twice as fast as Y and resulting archive size of X is 10% larger than size of Y. (Special thanks to Uwe Herklotz to get this formula right)

score_X = POWER(2; ((size_X / size_TOP) - 1) / 0,1) * time_X

with  score_X     efficiency score for a certain compressor X
      time_X      time elapsed by compressor X
      size_X      archive size achieved with compressor X
      size_TOP    archive size by top archiver (smallest benchmark result)

"0,1" represents 10% and power of 2 ensures that for each 10% worse results (compared
with top) the time is doubled, so any archiver (except top compressor) will get a
penalty on time. The score of top compressor is always equal to its time value.

Results sorted on Compression ratio.

Pos	Program	Switches used	TAR	Compressed	Compression	Comp time	Decomp time	Efficiency
				Size (bytes)	Ratio (%)	(sec)	(sec)	lower is better
001	PAQ8P	-7	N	62683172	80.19	42998	39835	42998
002	WinRK 3.0.3	Maximum	N	64217766	79.70	30603	29899	36263
003	PAQ8JC	-6 (dir /oen)	N	66191139	79.08	49154	42144	72448
004	PAQAR 4.5	-7e (dir /oen/b)	N	68435715	78.37	55430	55659	104714
005	WinRK 3.0.3	High	N	68947835	78.21	6317	3961	12629
006	PAsQDa 4.4	-7e	N	69109187	78.15	54855	55041	111640
007	NanoZip 0.04a	-cc -m800m	N	70082245	77.85	1059	996	2400
008	UDA 0.301	(none)	Y	71478767	77.41	7457	7472	19723
009	DURILCA 0.5	-m800 -t1	N	72175363	77.19	1997	1794	5705
010	DURILCA 0.5	-m800 -t1 -o32	N	72246808	77.16	1838	1628	5292
011	Slim 0.23d	-m800 -o64	N	73664683	76.71	3665	3605	12344
012	WinUDA 0.291	mode-3	N	73735574	76.69	7291	7263	24750
013	Slim 0.23d	-m800	N	73756703	76.69	3490	3491	11875
014	Slim 0.23d	(none)	N	73781973	76.68	3580	3524	12215
015	KGB 1.1 (PAQ6)	(very good)	N	75341375	76.18	15703	15801	63662
016	NanoZip 0.04a	-cO	N	75989377	75.98	557	103	2426
017	CCMx 1.30c	6	Y	77079949	75.64	369	357	1813
018	PPMonstr J	-m800 -o32	N	77699686	75.44	1672	1681	8798
019	CCM 1.30c	6	Y	77926922	75.37	293	281	1581
020	PPMonstr J	-m800 -o16	N	78086417	75.32	1628	1639	8941
021	FreeARC 0.50a	-mx	N	78215498	75.28	312	74	1738
022	UHARC 0.6b	-mx -md32768 -mm+	N	78344876	75.24	680	610	3843
023	PPMonstr J	(none)	N	78443862	75.20	1610	1620	9199
024	CCM 1.30c	(none)	Y	78598980	75.15	277	265	1610
025	LPAQ8	8	Y	78704186	75.12	1312	1321	7715
026	PIMPLE2	(none)	Y	79628157	74.83	5699	5731	37116
027	FreeARC 0.50a	(none)	N	79642328	74.83	188	65	1226
028	WinUDA 0.291	mode-0	N	79710669	74.80	2366	2359	15550
029	WinRK 3.0.3	Normal	N	80676067	74.50	614	154	4490
030	COMPRESSIA 1.0b	max sol dict 15 Mb	N	80698340	74.49	2081	99999	15256
031	NanoZip 0.04a	(none)	N	80802431	74.46	185	56	1372
032	DURILCA light 0.5	-m800 -t1	N	81666056	74.19	366	173	2986
033	EPM r9	-m800	Y	81934909	74.10	2497	2513	20988
034	CMM4 0.2b	26	Y	82435458	73.94	642	657	5703
035	EPM r9	(none)	Y	82727852	73.85	2328	2350	21360
036	SQUEEZ 5.5	Ultra 32Mb M E Solid	N	82801754	73.83	1262	72	11674
037	Ocamyd 1.66 test1	-m8 -s0	Y	82880385	73.80	12124	12119	113135
038	Quark 0.95r	-l7 -d25	Y	83673567	73.55	5438	90	55397
039	RZM 0.07h	(none)	Y	84030374	73.44	591	42	6263
040	FreeARC 0.50a	-m3	N	84466848	73.30	85	46	945
041	WinRK 3.0.3	Fastest ROLZ3	N	84652024	73.24	252	165	2860
042	SBC 0.970 rev3	-m3 -b62	N	84736176	73.21	253	92	2899
043	Quark 0.95r	(none)	Y	84741314	73.21	1818	89	20841
044	UHARC 0.6b	(none)	N	84954506	73.15	479	66	5622
045	SBC 0.970 rev3	-b9	N	85740265	72.90	134	71	1716
046	StuffIt 12.0	Method=2 L3 E25 bm=on	N	85892062	72.85	367	76	4778
047	SBC 0.970 rev3	(none)	N	86245288	72.74	127	70	1719
048	KGB 1.1 (PAQ6)	(normal)	N	86565142	72.64	2486	2527	34867
049	WinRAR 3.71	Best solid 4096Kb	N	86758171	72.58	172	54	2464
050	7-Zip 4.58b	Ultra solid LZMA 64Mb	N	87230789	72.43	338	17	5103
051	SQUEEZ 5.5	Max 8Mb M E Solid	N	87693302	72.28	347	36	5513
052	ENC 0.15	abies -d256	N	87955590	72.20	9088	99999	148646
053	COMPRESSIA 1.0b	sol dict 15 Mb	N	88152784	72.13	216	154	3611
054	CTXf 0.75	-me	N	88357992	72.07	208	159	3557
055	7-Zip 4.58b	Norm solid LZMA 16Mb ws=32	N	88470477	72.03	274	17	4744
056	WinACE 2.69	Max 4096Kb solid ace20	N	88485235	72.03	225	16	3902
057	ACE 2.04	-m5 -d4096	N	88486043	72.03	227	15	3937
058	WinACE 2.69	Norm 4096Kb solid ace20	N	88526291	72.02	191	16	3328
059	TC 5.2 dev2	(none)	Y	89464778	71.72	1107	1112	21395
060	ENC 0.15	-d256	N	89750528	71.63	3735	99999	74503
061	DGCA 1.10	(none)	N	89834304	71.60	209	80	4208
062	CTXf 0.75	(none)	N	90038884	71.54	165	116	3398
063	777 0.04b1	-mg -mu32	N	90229477	71.48	2767	1528	58196
064	WinRAR 3.71	Normal solid 4096Kb	N	90540300	71.38	152	10	3309
065	777 0.04b1	(none)	N	90544382	71.38	3151	1637	68621
066	LZPX(J) 1.2h	-8	Y	91451359	71.09	301	300	7247
067	Bee 0.7.9 bld 0316	-m3 -d8 -s	N	92003980	70.92	1693	1702	43327
068	PIM 2.10	(none)	N	92067900	70.90	259	275	6675
069	LZPX(J) 1.2h	(none)	Y	92075183	70.90	277	280	7145
070	BIT 0.3	-m lwcx -p good	Y	92135853	70.88	1046	1048	27162
071	BALZ 1.13	ex	Y	92654916	70.71	985	101	27089
072	Bee 0.7.9 bld 0316	-m2 -d8	N	93103491	70.57	934	948	26993
073	UFA 0.04b1	-mg -mx -mu32	N	93428292	70.47	1348	352	40383
074	DST 0.91b	-me	Y	93568347	70.42	624	469	18985
075	SQUEEZ 5.5	Norm 4Mb M E Solid	N	94082622	70.26	132	36	4251
076	UFA 0.04b1	(none)	N	94175638	70.23	901	102	29317
077	FreeARC 0.50a	-m2	N	94526286	70.12	32	29	1082
078	ACB 2.00c	u	N	95055289	69.95	2738	2870	98191
079	BOA 0.58b	-m15 -s	N	95080468	69.95	2003	2036	72033
080	BMA 1.35b	-m16m -ax -mx	N	95284418	69.88	255	150	9380
081	PPMN 1.00b1 km	-O9 -M:50 -DA	Y	95513817	69.81	675	678	25466
082	BSSC 0.95a	(none)	Y	95811218	69.71	127	57	4952
083	StuffIt 12.0	Method=5 E26 bm=on	N	96069139	69.63	136	152	5456
084	CABARC 1.00.0106	LZX:21	N	96412288	69.52	598	7	24918
085	WINZIP 11.0	Optimize for best comp.	N	96420110	69.52	156	158	6506
086	PPMVC 1.2	-o16 -m256	N	96525071	69.49	325	375	13712
087	DC 0.99.307b	-b4096	N	96592918	69.47	133	99999	5654
088	PPMd var J rev.1	-m256 -o16	N	96737515	69.42	172	192	7429
089	DURILCA light 0.5	(none)	N	96823376	69.39	178	189	7762
090	BOA 0.58b	(none)	N	96857515	69.38	1541	1605	67452
091	BIX 1.00 b7	-mdG -s	N	97079141	69.31	348	10	15610
092	PPMVC 1.2	(none)	N	97152520	69.29	206	256	9316
093	WINIMP 1.21	1 BEST MM 16Mb B=1020Kb	N	97241095	69.26	204	9	9316
094	GRZipII 0.2.4	-b8m -a	Y	97484136	69.19	117	104	5489
095	7-Zip 4.58b	Max PPMD 64Mb ws=16	N	97573749	69.16	207	234	9807
096	FlashZIP 0.91b	-m2 -s7	Y	97655138	69.13	748	45	35760
097	WINZIP 11.0	PPMd	N	97754314	69.10	181	197	8749
098	StuffIt 12.0	Method=3 E25 bm=on	N	98017538	69.02	233	122	11595
099	Blizzard 0.24b	(none)	Y	98296282	68.93	149	128	7647
100	MNZIP	(none)	Y	98488045	68.87	280	64	14678
101	QC 0.050	-8	Y	98510933	68.86	1865	576	98011
102	BMA 1.35b	(none)	N	98728900	68.79	132	95	7106
103	WinHKI 1.74	HKI2 max	N	98771075	68.78	312	319	16875
104	EPC 1.0	-m256 -o18	Y	98797159	68.77	382	99999	20721
105	WINIMP 1.21	1 BEST MM	N	99025199	68.70	137	9	7621
106	QC 0.050	(none)	Y	99055044	68.69	665	250	37115
107	LZPM 0.15	9	Y	99083654	68.68	1615	28	90421
108	UHARC 0.6b	-mz -md32768 -mm+	N	99251157	68.63	72	81	4107
109	DC 0.99.307b	(none)	N	99517116	68.54	124	99999	7283
110	BIX 1.00 b7	(none)	N	99694432	68.49	237	10	14196
111	BioArc 1.9	Ultra	N	99699058	68.49	164	191	9829
112	BA 1.01	(none)	Y	99873098	68.43	146	97	8920
113	M03	(none)	Y	99934651	68.41	3519	568	216464
114	Tornado 0.4a	-11	Y	99959838	68.40	249	13	15359
115	BioArc 1.9	Normal	N	100012777	68.39	158	185	9803
116	WinHKI 1.74	HKI2 norm	N	100208006	68.32	230	237	14582
117	WINIMP 1.21	Normal MM	N	100399936	68.26	82	9	5310
118	UHBC 1.0	-b4m -m3	Y	100623220	68.19	460	399	30535
119	DARK 0.51	-b128m	N	100785450	68.14	152	93	10272
120	DARK 0.51	(none)	N	100877062	68.11	149	91	10172
121	BruteCM 0.1d	(none)	Y	100902600	68.10	271	407	18553
122	UHBC 1.0	(none)	Y	100990062	68.08	363	296	25093
123	WinRAR 3.71	Fast solid 4096Kb	N	101008351	68.07	125	12	8658
124	JAR 1.02	(none)	N	101169071	68.02	89	16	6275
125	PPMN 1.00b1 km	(none)	Y	101181370	68.02	501	509	35373
126	QLFC 6.6w	BS=8388608	N	101217544	68.01	1793	78	127103
127	EPC 1.0	(none)	Y	101258666	67.99	209	230	14883
128	GRZipII 0.2.4	(none)	Y	101686370	67.86	118	110	8810
129	M99 2.2.1	-m 512m	Y	101746662	67.84	215	197	16159
130	ZZIP 0.36c	-mx -a -6m	N	102392643	67.63	4146	100	334687
131	CABARC 1.00.0106	LZX:17	N	102561882	67.58	175	7	14394
132	PPMd var J rev.1	(none)	N	102743525	67.52	122	141	10238
133	QLFC 6.6w	(none)	N	102938276	67.46	883	71	75714
134	WinTurtle 1.60	Solid	N	103129672	67.40	73	79	6393
135	DACT 0.8.41	-b1000000	Y	103176088	67.39	727	37	63998
136	DACT 0.8.41	(none)	Y	103378718	67.32	735	41	66169
137	DST 0.91b	(none)	Y	103386376	67.32	287	118	25859
138	WinTurtle 1.60	(none)	N	103567658	67.26	64	71	5883
139	ABC 2.4	(none)	Y	103669744	67.23	1200	194	111564
140	ZZIP 0.36c	(none)	N	103845404	67.17	1827	100	173187
141	Bicom 1.01	(none)	Y	103940513	67.14	2140	2172	205002
142	PACKET 0.90b	-m4 -s9	Y	104524024	66.96	778	20	79496
143	QazaR 0.0 pre5	-d9 -l7	Y	104867105	66.85	922	257	97853
144	YBS 0.03f	(none)	Y	105074083	66.79	140	70	15202
145	ASD 0.2.0	-m5 -mdg	N	105109740	66.77	6296	415	686373
146	RZIP 2.1	-9	Y	105305418	66.71	161	61	17936
147	RZIP 2.1	(none)	Y	105417723	66.68	137	57	15453
148	UC II 3.05	(none)	N	105608406	66.62	313	10	36057
149	Tornado 0.4a	(none)	Y	105742922	66.57	27	13	3157
150	SZIP 1.12	-b41 -o40	Y	105793183	66.56	963	193	113225
151	RINGS 1.5c	5	Y	105800703	66.56	72	74	8472
152	CHILE 0.3d	(none)	Y	106072542	66.47	890	157	107925
153	CHILE 0.3d	-b=2048	Y	106165564	66.44	1092	160	133790
154	UC II 3.05	-TT	N	106353574	66.38	136	11	17013
155	BBB ver1	m512	Y	106364761	66.38	31957	1321	4002515
156	WinHKI 1.74	HKI1 max	N	106391218	66.37	158	39	19847
157	SZIP 1.12	(none)	Y	106567179	66.31	134	70	17163
158	ShipInBottle 1.0 b17	alg:ppm :mem:128	N	106742422	66.26	4204	4243	548993
159	QUAD 1.12	x	Y	106968291	66.19	176	55	23565
160	AI 1.1	-mt	N	107365151	66.06	70444	98105	9854934
161	YBS 0.03f	-m16m	Y	107462346	66.03	181	89	25595
162	HA 0.999b	a21	N	107637414	65.98	961	360	138551
163	BZIP2 1.0.5	(none)	Y	107720923	65.95	138	35	20080
164	QazaR 0.0 pre5	(none)	Y	108165979	65.81	155	109	23692
165	QUAD 1.12	(none)	Y	108215434	65.79	106	55	16291
166	M99 2.2.1	(none)	Y	108294876	65.77	130	72	20156
167	ASD 0.2.0	(none)	N	109101360	65.51	404	137	68481
168	KZIP 14-APR-2007	(none)	N	110694932	65.01	4719	8	954046
169	M1 0.1a	paq	Y	110795709	64.98	233	237	47634
170	TarsaLZP 21Aug2007	(none)	Y	110994614	64.91	94	114	19644
171	HOOK 1.3	800	Y	111275351	64.83	244	253	52600
172	SEMONE 0.6 b2	(none)	Y	111442686	64.77	204	28	44798
173	BZP 0.3	(none)	N	111485802	64.76	34	36	7502
174	WINZIP 11.0	Enhanced Deflate	N	111503290	64.75	112	9	24760
175	LHARK 0.4d	-tob	N	111870915	64.64	83	8	19111
176	THOR 0.96	e5	Y	112275112	64.51	24	6	5779
177	MAR	-g	N	112554786	64.42	252	10	62580
178	TURTLE 0.07	(none)	Y	112646749	64.39	88	83	22077
179	LHARK 0.4d	(none)	N	113439063	64.14	37	8	10132
180	LZ2A	-Cb12 -Szd26	Y	113588897	64.09	350	41	97447
181	PKZIP 2.50	-exx	N	114022347	63.96	28	8	8178
182	ShipInBottle 1.0 b17	alg:lz	N	114051091	63.95	1244	49	364516
183	SLUG 1.27b	(none)	Y	114187051	63.91	12	11	3569
184	LZXQ 0.4	normal	Y	114492987	63.81	177	273	54462
185	PKZIP 2.50	(none)	N	114501263	63.81	22	8	6775
186	AMG 2.2	(Max Compression)	N	114662758	63.76	244	99999	76500
187	VuZip 1.8	Max	N	114679608	63.75	89	11	27956
188	DZip 2.90	-9	N	114688490	63.75	76	8	23896
189	EAZEL 1.0	(best)	N	114728370	63.73	99	12	31265
190	CODEC 3.21	(none)	N	114767275	63.72	62	44	19664
191	GZIP 1.2.4	-9	Y	114857977	63.69	67	7	21464
192	AIN 2.32	-m1	N	115160947	63.60	94	7	31140
193	ESP 1.92	(none)	N	115164577	63.60	32	8	10605
194	LZTurbo 0.92	-43	Y	115219801	63.58	34	18	11337
195	VuZip 1.8	Default	N	115261129	63.57	41	11	13734
196	DZip 2.90	(none)	N	115269882	63.56	33	8	11065
197	LZ2A	(none)	Y	115298983	63.55	305	44	102595
198	File2Pack 2.0	(none)	N	115305901	63.55	32	8	10772
199	EAZEL 1.0	(normal)	N	115309762	63.55	44	11	14818
200	GZIP 1.2.4	(none)	Y	115442964	63.51	28	7	9570
201	AIN 2.32	(none)	N	115576936	63.47	25	7	8672
202	BCArchive 1.08.7	(none)	N	115821124	63.39	41	28	14611
203	ARJ32 3.14	(none)	N	116105225	63.30	41	9	15077
204	ARJ 2.84	(none)	N	116107572	63.30	53	10	19495
205	WINZIP 10.0	Normal	N	116113423	63.30	31	9	11410
206	WinXP (Built-in)	(none)	N	116337271	63.23	28	30	10564
207	aPLib 0.43	(none)	N	117596762	62.83	650	10	281894
208	SR3a	(none)	Y	118183199	62.64	53	59	24525
209	ALZip 7.0b1	(normal)	N	118492877	62.54	36	14	17239
210	HPACK 0.79a	(none)	N	120702014	61.85	973	74	594857
211	SAR 1.0	(none)	N	122067423	61.41	236	20	167797
212	SYMBRA 0.2	-m5	Y	122120558	61.40	2879	1733	2059045
213	AR 1.0	(none)	Y	122147342	61.39	242	20	173590
214	DeepFreezer 1.06	(none)	N	123350351	61.01	45	15	36872
215	Chaos Comp 3.0	(none)	N	123681560	60.90	73	14	62046
216	Ocamyd 1.66 test1	(none)	Y	124262690	60.72	519	518	470398
217	THOR 0.96	e3	Y	124588656	60.62	6	7	5638
218	LCSSR 0.2	-l9 -b6	Y	126378787	60.05	7578	7233	8679130
219	HYPER 2.5	(none)	N	128439870	59.40	55	32	79116
220	LZOP 1.02rc1	-9	Y	129601733	59.03	132	7	215911
221	ARX 1.0	(none)	N	133464199	57.81	84	21	210606
222	QuickLZ 1.40b9	mode3	N	133973909	57.65	21	9	55704
223	CTW 0.1	(none)	Y	134687380	57.43	6911	7405	19836944
224	Secura Archiver 1.7	(none)	N	139876348	55.79	334	7	1701671
225	CA-ZIP 3.4	(none)	N	140247762	55.67	61	8	323814
226	AI 1.1	(none)	N	140259735	55.66	9153	15193	48652416
227	LZTurbo 0.92	-21	Y	144135815	54.44	6	7	48960
228	ASH 04a	-m800 -s80 -o60	Y	144885507	54.20	3229	2182	28625779
229	LZC 0.08	2	Y	149651909	52.70	33	14	495570
230	BriefLZ 1.04	(none)	N	151611876	52.08	19	6	354381
231	THOR 0.96	e1	Y	151936954	51.97	3	6	58003
232	LZW 0.2	(none)	Y	153289520	51.55	645	15	14482507
233	LZOP 1.02rc1	-1	Y	154993814	51.01	7	6	189771
234	LZOP 1.02rc1	(none)	Y	155389089	50.88	7	6	198249
235	QuickLZ 1.40b9	mode1	N	156840006	50.42	3	9	99750
236	BigCrunch 0.4a1	(none)	N	157502600	50.21	1411	3829	50482427
237	CODER 1.1	-ew 4194304	N	158788621	49.81	849	274	35017153
238	SRANK 1.0	(none)	Y	164110929	48.12	13	13	965862
239	TESTSET		N	316355757	0.00	0	0	0

Remarks:
Ten programs so far crashed during compressing:
- Emilcont 0.3a
- RKC 1.02
- PPMZ2 0.81
- HIPP 0.5819
- OrangeArchiver 1.05
- PPMT 1.0
- HIP beta1
- LZ 1.0
- HuffComp 1.3
- Chile 0.5

- Some programs fail to correctly decompressing the archive created. Those programs are marked with a red penalty time of 99999 seconds. Do *not* use these programs to backup your data!.

- (De)compression time of ACB 2.00c is an approximation as ACB only runs under Win98 (which is installed on the 1800+ machine only). Measured time on the 1800+ is devided by the approximate ratio of compression speed on both machines.

- The command-line version of Squeez 5 seems to get different compression then the GUI version. The switch combination '-m5 -MD32768 -uxx9 -ME -MM -s' gets it down to 83.384.794 bytes...
- Stuffit 12.0 contains recompression techniques for several file types like JPG, GIF, BMP and PDF. For the MFC test I disabled PDF recompression as it appears to be "pixel perfect" rather then "bit-perfect" for most PDF files. This hurts compression a bit, but prevents the decompressed file to be slightly different than the original. This would be fine for normal users, but this is a lossless compression test. It would be unfair towards the lossless "bit perfect" compressors to include these result.

Conclusions and observations:
- Top performers (based on compression) in this test are PAQ8 and WinRK (PWCM). They are able to compress the 300+ Mb testset to under 62 Mb (80% reduction in size) but take a minimum of 8,5 hour to complete the test. The number one program (PAQ8P) takes almost 12 hours and number four (PAQAR) even 17 hours to complete the test. WinRK, the program with the 2nd best compression (79.7%) takes about 8,5 hours. Not surprisingly all mentioned programs make use of a PAQ(-like) engine for compression. If you have files with embedded images (e.g. Word DOC files) use PAQ8, it will recognize them and separately compress them, boosting compression significantly. All mentioned programs (except the current number 2, WinRK) are free of charge.

- WinRAR but especially NanoZip, FreeARC, SBC 0.970 and CCM score very well on efficiency, they have good compression and are reasonably fast. FreeARC and NanoZIP are capable of compressing the testset down to 79 Mb in under 3 minutes. CCM takes just under 5 minutes. SBC compresses to about 85 MB but only needs 2 minutes for that. People looking for good (but not ultimate) and fast compression should have a look at those programs. Of the mentioned programs NanoZIP and CCM have the best compression, SBC and FReeARC are the fastest (FreeARC being both faster and the better compressor). Best 'super' compressor with a not to dramatic compression time is NanoZip, compressing then MFC testset to under 69 MB in 18 minutes using CM-mode.

- The speed-kings in this test are THOR, QuickLZ, SLUG and LZOP, the first two compress the total testset of 300+ MB in under 3.4 seconds (which generates a total data stream of 300 MB input + 150 MB output / 3.5 sec = 128 MB/s). At this speed IO/harddisk performance has a large impact on the compression speed, when compression from-to memory probably even higher compression speeds are possible. As a consequence of this speed compression ratio is not very high (barely 50%). Other fast compressors, with a bit better compression, are the oldies Pkzip, Arj and Gzip. If you are looking for a fast compressor with still good compression, consider UHARC 0.6b using LZP-mode (-mz) or FreeARC in m1 or m2 mode.

- Decompression speeds are usually a lot faster then compression speeds except for the compressors using a PPM or PAQ-engine. Decompression times of 5-7 seconds seem to be the systems (IO/hardisk) limit; compressing to ramdisk (or /dev/null) should probably be even faster...

- Normally I would expect 7-Zip to outperform WinRAR, but in this case I suspect WinRAR beats 7-Zip because there are (embedded) multimedia files (wav,bmp etc) which can be handled by WinRAR's multimedia filter. 7-Zip still lacks such a filter. I included multimedia files because many games are distributed in compressed form (games typically have lots of bmp and wav-like files).

- The higher the fraction of pre-compressed files the smaller the difference between the top and the other compressors. Because the testset contains files like chm,gif,jpeg the difference between the compressors looks rather small. I will probably make a 2nd testset with easy to compress non-multimedia data later on.