FAQs are a good thing; this is right off SiSoft's page.
Q: Why is Sandra (2002 and later) memory index so high compared to other benchmarks?
A: This is due to using the latest instruction sets and techniques (see above) for obtaining the highest possible efficiency and thus performance out of the system. This should show what the system is able to do.
Here's some others you may find interesting...
Q: Why is Sandra (2001 and earlier) memory index so low compared to other benchmarks?
A: Most other benchmarks just read or write to memory without performing any data manipulation. In real-life, no program works this way - why read something if you don't actually use it? Sandra creates 3 large arrays and performs various simple arithmetical computations on them - thus reading and writing memory. We feel this is a more objective test which measures the real throughput of the system. By using large blocks of memory (8MB+), the system cache(s) are swamped, thus the actual memory throughput is measured. Of course, the cache does have an effect - unless it is turned off.
If you compare Sandra's results with other benchmarks' (e.g. WinTune 98) large blocks copy speed, you'll find the results are comparative.
Q: My non-Intel chipset (VIA, SiS, Ali) gets very low memory index.
A: Check that the memory settings are optimised. Most of these chipsets must be aggressively tweaked to match AMD/Intel ones. Do note that most of these chipsets are value and not performance and thus cannot be expected to match it.
Q: My Intel 840 (2 RDRAM PC800 channels) gets nowhere near a 3.2GB/s index! Why?
A: The 840 is greatly FSB limited (1x 133MHz, 64-bit -> 1GB/s); furthermore, both processors share the FSB. With PIII Coppermine CPUs, single thread, Sandra 2002 gets close to 90% bandwidth efficiency which is correct. An 820 with a single RDRAM channel (1.6GB/s) gets very similar scores since it is FSB limited also. You could consider the 2nd channel of the 840 superfluous.
Q: My VIA Apollo266 (1 DDR PC2100 channel) gets nowhere near 2.1GB/s index. Why?
A: Just like the 840, the chipset is FSB limited, also both processors (in SMP mode) share the FSB.
Q: My Intel 845 (1 SDRAM PC133 channel) gets "low performance memory warning". What's wrong?
A: The maximum bandwidth of a single PC133 SDRAM @ 1GB/s is around 32% of the FSB bandwidth of the Pentium 4. The processor is starved for bandwidth which results in low performance. Both Athlon & Pentium 4 need DDR or RDRAM memory for good performance.
*edit*
HERE'S THE LINKY TO THE WHOLE MEMORY FAQ.
