Core 2 Duo Cache Memory and Performance

Since new Core 2 Duo E6x20 processors with larger L2 cache memory will be priced just as the Allendale based CPUs working at the same frequencies (this core is the same Conroe core with reduced L2 cache), it will be extremely interesting to find out how the performance of CPUs on Core micro-architecture depends on the size of the L2 cache. Therefore, we decided to compare the performance of the Core 2 Duo E6420 and Core 2 Duo E6400 side by side in the most popular applications. The obtained results are given in the table below:

	Core 2 Duo E6420 4MB L2	Core 2 Duo E6400 2MB L2	Performance Hit
3DMark06	5948	5928	0.3%
3DMark06, CPU	1797	1774	1.3%
PCMark05	6673	6582	1.4%
PCMark05, CPU	5196	5174	0.4%
Word 2007 (Document Compare), sec	51	54	5.9%
Excel 2007, sec	14.4	18.4	27.8%
7-Zip 4.44, Compressing, KB/s	3023	2789	8.4%
7-Zip 4.44, Decompressing, KB/s	21076	20983	0.4%
MPEG-4 Encoding, AutoGK 2.4/Xvid 1.2, fps	32.16	30.91	4.0%
H.264 Encoding, Apple Quicktime Pro 7, sec	493	498	1.0%
mp3 Encoding, Apple iTunes 7, sec	156	157	0.6%
Adobe Photoshop CS3 (ps7bench 2.0), sec	105	107	1.9%
Windows Photo Gallery (Print), sec	31	32	3.2%
Adobe Premiere Pro 2.0, sec	245	246	0.4%
Windows Movie Maker, sec	102	103	1.0%
3ds Max 8 (Space Flyby), sec	263	265	0.8%
CINEBENCH 9.5, Rendering	694	693	0.1%
POV-Ray 3.7	829.1	820.1	1.1%
Quake 4, 1024x768 High Quality	90.01	83.24	8.1%
F.E.A.R., Medium Quality	104	98	6.1%
Unreal Tournament 2004, 1024x768	79.9	76.8	4.0%
Company of Heroes, 1024x768	115.4	112.6	2.5%
Valve VRAD map build benchmark, sec	335	336	0.3%
Valve Source Engine particle benchmark	34	31	9.7%
Fritz 9 Chess Benchmark	3106	3078	0.9%

The results we obtained in 22 popular applications prove that cache size does have significant influence on the system performance. Although the average advantage of the Core 2 Duo E6420 over Core 2 Duo E6400 equaled only 3%-4%, the actual performance gain depends a lot on the type of workload.

Office applications and games stand out among all other benchmarks. In this type of applications cache poses the biggest influence on the system performance. In both: contemporary games as well as typical office tasks, Core 2 Duo E6420 can be as much as 6-8% faster than Core 2 Duo E6400. There are even greater examples of the practical value of the large L2 cache. For instance, Valve Source Engine particle benchmark that shows the processor performance when calculating the physical model of the gaming world demonstrates a 10% performance advantage of the newcomers over the older processor models. But the most impressive result of all can definitely be observed in Excel 2007. The CPU with 4MB L2 cache hit the impressive performance gain of 27.8% during typical statistical operations.

However, there are also some applications where L2 cache memory has very little influence on the results. Here we could list final rendering tasks as well as some sound, video and image editing procedures.