Problem adding new RAM

[Gome]

Hello ppl.

I just bought a new 1GB memory module, kingston valueram pc5300/667MHz. Previously I'm using a 512MB module, also kingston valueram pc5300/667MHz.

The problem I encountered is that whenever I use 2 of these modules together, my pc won't boot. It'll give me the 'unable to detect dram' kind of beep. I'm using a biostar geforce 6100 am2 mobo btw. When I use just the 1GB module alone, my pc boots correctly. My pc also boots correctly when I use the 512MB module alone.

What I've done so far:

-Cleaned/vacuumed all the DIMMS. Still the same

-Changed the cmos battery, suspecting that it might have weakened since it kept reporting something like "cmos check error, please re-setting cpu frequency...". Still the same.

-Flahsed my bios to the latest version. Still the same.

-Only when I manually changed the memory clock from 'auto' to 533MHz, can my pc become alive again. It won't run if I set it to 667MHz.

I've checked the 2 sticks of ram with cpu-z and verified that they're both pc2-5300. The 512MB module was manufactured in week 33, year 06. The 1GB module manufactured in week 01, year 07.

So any idea on what's preventing my mobo from running the rams at 667MHz?

Thanks.

 

[CrazeD]

What are the timings of both sticks?

 

[zep867]

what processor are you using?

 

[Gome]

I've checked with cpu-z (using only 1 stick at a time) and they're both 5-5-5-15. I'm using a Sempron AM2 3000+ proc.

 

[WorldIndustries]

You sure you're not putting them in two dual channel slots?

 

[Gome]

Currently it's in dimm0 and dimm2 (I have 4 slots, dimm0->dimm3). I've tried other configurations too, but still the same problem.