Memory OK @ 100, Not @ 133

[Randy_77]

I run a Shuttle AK-11 main board with AMD Athlon 800MHz processor and 3 sticks of 128MB/133MHz memory. Operating Sysyem in WinXP Pro.
All runs fine when BIOS is set to "DRAM Clock" = 100 (choices are 100 and 133), but system will not boot when this clock is set to 133.
Benchmarks, such as MadOnion and PCMark, seem to indicate that the memory is in fact performing at 100 levels when set to 100, as I would expect.
Other settings, such as "SDRAM Cycle Length" (2 or 3 - I normally use 2) and "Bank Interleave" (4, 2 or 0 - I normally use 4) seem to have no effect on ability to run at 133.
Does anyone have any ideas on why a system that apparently should support 133, with proper 133 memory sticks installed, might not run at 133?
Thank you in advance for any suggestions...

Randy

[ski]

Are all 3 memory modules definitely 133 MHz?
Sometimes suppliers will label them as such, but they really are only 100 MHz.

Also, are they all from the same supplier, and are they quality brands(Crucial, Mushkin, Corsair, or Kingston)?
Mixing memory from different suppliers, especially bargain brands, can cause the problem you're having.

[gwallen4]

Unmatched Sdram sticks can be a problem. Also one stick may not be performing to specs. Try various combinations of one or two sticks at 133 to see if there is a bad stick.

If you can get it to boot at 133, DocMemory (see link below) can be used to test memory. It's free!

http://www.simmtester.com/PAGE/products/doc/docinfo.asp

Finally, there are "memory experts" on this forum that will be along shortly.

[mjc]

That about covers it until you find out for sure if all your sticks are true PC133 SDRAM...

[ranchdog]

Sir...

It won't boot because the 800 CPU
is using a Front Side Bus of 100 and
a multiplier of 8x.

Then you are going into BIOS and trying
to make your RAM run with a Bus Speed
of 133.

With the Mboard/CPU combination you are
using the memory will have to hum
along with a setting of 100.


RD.

[Randy_77]

ranchdog,
Thanks. Your explanation makes sense.
It's not that I'm unhappy or anything, I was just curious.
Testing was real bugger, had to reset BIOS each time I tried anything at 133.
Next mobo will be DDR, wish me luck!

[gwallen4]

According to the Shuttle AK-11 manual you should be able to set the Sdram clock at 133 with a FSB/CPU clock of 100. Or am I reading it wrong?

[Randy_77]

I don't think you are reading the manual wrong. That's how I read it too, it just doesn't work that way. I have overall liked the Shuttle board, good value and no trouble to speak of, and in reality I don't think I'm leaving that much performance on the table. Next mobo, I'll look a like more closely at FSB/Processor/Memory Speed interelationships. Now, I'm just waiting for the new Serial ATA hard drives and the Via333 chipset boards to come out.