how do i get my pc3200ddr ram to run at 400m

  tabbatha 19:52 29 Jan 2004

i have a abit kd7 mobo, it supports pc3200ram.
how can i get this to run at 400mhz.


The memory will only run as fast as the front side bus will allow it to, in most cases this is 166mhz x 2 = 333Mhz for PC2700DDR Ram.

If you already have PC3200 DDR Ram (which is what is needed for 400Mhz FSB) then your mobo must support 200Mhz FSB (or 200 x 2 = 400). If not then the only way is to try "overclocking" the FSB in the bios.

For example, I run an Athlon XP3000 that has a stated FSB of 400. My memory is PC3500 and to get it to run at its maximum I have "tweaked" the FSB to 218Mhz for a total of 438Mhz FSB. My XP300 is now also reported as a Athlon XP3200.

  bremner 20:44 29 Jan 2004

As your board supports DDR400 the BIOS should automatically detect it and run it at 400Mhz.

  cream. 20:50 29 Jan 2004

As Smiffy99 says the memory will only run as fast as the fsb. The manual for the abit kd7 states that the fastest memory is pc2700 ( 333Mhz).

Are you sure it supports pc3200?

You can look in the bios under advance chipset features and click on the dram clock / drive control. This will give you the fastest speed for your ram.

Hope this helps.

  bremner 20:57 29 Jan 2004

According to this it does click here likewise the KD7-A, KD7-G, KD7-Raid & KD7-S

  DieSse 22:02 29 Jan 2004

A couple of comments

"supports" can sometimes mean you can fit it and it will work - not that it actually runs at that speed.

RAM does not always run at the FSB speed - it can have it's own speed setting in the BIOS - usually one notch above or below the FSB speed.

  bremner 08:36 30 Jan 2004

To avoid bottlenecks the RAM should never run slower than the FSB of the processor.

Therefore I don't really understand the statement "one notch above or below the FSB"

  DieSse 08:45 30 Jan 2004

Because that's the way many motherboards are designed - the RAM doesn't have to run at the same speed as the FSB.

Yes, it's not necessecarily the most efficient way, but it is allowed.

  temp003 08:54 30 Jan 2004

Agree with DieSse on both counts.

If your CPU runs at FSB of 166MHz, it can't run the RAM at 200MHz. This is a limitation of the VIA KT400 chipset itself used by the motherboard. This is according to the Abit website. If you use such a CPU, you won't get an option in BIOS to run the memory at 200MHz.

If your CPU runs at a FSB of 100MHz or 133MHz, but the motherboard still can't run the PC3200 RAM at 200 MHz, then it could be down to compatibility with the chipset. Although the VIA KT400 chipset was intended to support DDR400 (hence the name), it turned out that during testing, it didn't do so well with some DDR400 memory, so VIA had to withdraw official support for DDR400 with this chipset. It doesn't mean it won't run DDR400, just that some DDR400 won't run or won't run well.

Individual motherboard makers may still say that their mobos with this chipset support DDR400. Many specify which brands and modules of DDR400 which have been tested, and some specify that it only supports how many banks of DDR400 (Abit says 4 banks, so it should be OK).

  bremner 17:51 30 Jan 2004

I accept your point that boards are capable of running the RAM at different speeds to the FSB.

My point is that it is never advisable to have the RAM running at a speed slower than the processor as this causes a bottleneck which can result in problems with the machine.

  Rayuk 19:20 30 Jan 2004

click here

If you are running an Athlon [166/333] fsb cpu you cannot run the memory at 200/400 its a limitation of the chipset,which I think was rectified with the via400A+ chipset

This thread is now locked and can not be replied to.

Elsewhere on IDG sites

iMac Pro review

Illustrator Charles Williams on how to create magazines and book covers

iMac Pro review

Les meilleures prises CPL (2018)