Ram not reaching expected speed?

[rowdy81]

I recently put together a new computer with a Gigabyte motherboard (400FSB, VIA KT600 chipset, DDR400) and put in 512MB of PC3200 Kingston Ram. I read that using this setup its capable of up to 3.2GB/s but normally around the high 2’s. When I ran a Memory Bandwidth Benchmark using SiSoftware Sandra I got just over 2.1GB/s.

When I first ran up the computer I also has a 256MB chip of PC2100 Ram, and found out that it would slow my 3200 ram down this the slower 2100 speed ram. I have since removed it to see if I could get the approx figures that Sandra said I should get with the KT600 chipset and DDR400 ram. But no luck.

Does anyone know if that’s normal for a 400FSB with DDR400 and AMD Athlon XP 2600+ Barton. Any another thing, what is the main advantage of really fast RAM, does it help the CPU?

 

[Charles Hammond]

When you use that one stick of PC2100 Ram you are limiting all the RAM to the speed of the slowest RAM. Your processor has to wait for the RAM to process requests for memory access, so it really forces the Processor to slow down as well.

On the other hand if you have a processor with an FSB of 333 and run PC3200 Ram or DDR400 Ram, You can not take full advantage of memory designed to run faster than the processor.

Your computer may run faster if you pull out the PC2100. Of course you will then have less memory and it may have to write more Memory Pages to the hard drive. Which would slow it down for another reason.