HT & FSB doubt

[vvume]

What is the logic behind having a HT value > FSB on AMD 64 cpus? After all the HT still has to wait for the FSB to send in data. I can possibly see it affecting inter-cpu/core communication since they happen over internal HTs, but not with the main memory. Can someone enlighten me?

The question I ask is because my system crashes if I set any HT value > 200 (1x) with my FSB=200. I simply haven't found the reason why. My machine is rock solid at HT=200 and I even managed to overclock my X2 4400+ to 2651MHz with little effort. SiSandra and Matlab shows excellent scaling on par with published FX-60 results.

overclock specks: MSI K8T Neo2-FIR, 4*512MB OCZ Premier 2.5-3-3-6-2T, ATI 9600XT AGP, stock cooler, 5% CPU voltage increase, FSB=241;ASync DDR 333=DDR400 after overclocking, temps 32-40.

 

[TSS]

AMD systems dont have a fsb... fsb is intel. the HTT bus directly connects the CPU's memory controller (which is on-die with amd, intel doesnt have that) to the memory.

its known that AMD systems do have instability with any HTT higher then 1000. remember, you need to multiply the HT value by 5, which is standard. so when your trying to set 200, your really setting 1000. there should be a option somewhere to decrease the multiplyer. might be on auto, which is the same as 5. lower that so that the final value ends below or on 1000.

so if your running 241 fsb, you need to have a HTT multiplyer of 4, meaning your final HTT speed will be 241*4= 964. if you go higher then 250 HTT, reduce it to 3x. going higher then 333 HTT (unlikely your mobo can handle it) turn it down to 2x. look to the quick n dirty OC guide for more info.

http://forums.anandtech.com/messageview...atid=28&threadid=1497607&enterthread=y <<< linky to it.

 

[vvume]

My MB does not come with a HT multiplier, only a HT value (I guess this is in lieu of the multiplier). Take a look at the BIOS screen:
http://www.geocities.com/vvume_inq/Bios.gif

The values I can set for the HT Frequency are 200, 400, 600, 800, 1000. Anything other than 200 crashes my windows xp.