[AMD] Questions about HT Multiplier

Question

Ok i have a question about the HT multiplier in my bios on my sli/plat, it is currently and always set to 5x does this make a possible issue running my ram the ocz ram at the rated timings of 2 3 2 6 at 1t.  i can only run it now at 2.5,3 2 6 2t at 2.65 volts. the only stable settings.  I do not want to overclock i just want to know the whole meaning about the HT x5 and the difference of the x4
Thanks in advance
Andrew

Answer 1

Good question, its all how you set your fsb.  The default fsb is 200.  The hypertransport bus speed is the combination of the fsb and ht multiplier which at default speeds is 200x5=1000.  The platinum sli is rated for a hypertransport bus speed of 1000 and you will see that in the specs.  So thats why you can post at x5 with your fsb set at 200.
The second item that is based upon the fsb is the cpu speed which also has a multiplier.  For 3000 chips, the max multilplier is 9; for 3200 its 10 and for 3500 its 11.   So the default cpu ghz speed for the 3000 is 200x9=1.8 ghz which is its rated speed.  The 3200 is 200x10=2.0ghz and the 3500 is 200x11=2.2ghz at default....you will see that in the specs for each chip.
The tricky issue is when you overclock...which has been the big issue for a lot of us.  In my case, my pc4000 crucial ballistix tracer ram is stable at 245fsb (8 hours prime95 & memtest both) at memory timings of 2.5,2,2,5 1T.  That means, because I have a 3000, my effective cpu speed is 245x9=2.2 ghz.  In effect, I purchased a 3000 but am getting the performance of a 3500 because of the overclock.
However, the big problem is with the ht mulitplier.  Theoretically, I should be able to set the ht multiplier to x4...because 245x4=980 which is still below the rated hypertransport bus speed maximum of 1000.  But for most of us, we have to use clockgen to get there becuase the current bioses wont let us cold boot post beyond 219.  Therefore, its really the 219 cold boot hypertransport bug!
Why is this important.  In a few of my tests and others, the hypertransport bus speed is how fast your memory will interact with the rest of the components of your system...namely the video card(s) and your hard drives.  The lower I have to set the multiplier (the farther I get away from 1000) the lower the performance of the these components...especially the video card performance.
When you are playing games like first person shooters, etc, where you need a lot a frames per second so you dont get choppy graphics, the hypertransport bus speed really becomes an important issue.  I dont want to look at choppy or slow motion pictures and I am sure nobody else would either.
Aicjofs tested his winchester and venice core 90nm chips and his memory on 2 other name brand motherboards and he was able to cold boot post at 250fsb with the ht multiplier at x4.  So we know other motherboard manufacturers had bios problems earlier but fixed them, we are just waiting for MSI to do the same. 
Now I may not have this totally technically correct, but this is close enough.  Hope this helps.