Performance I cannot explain

[BoboKatt]

Good day everyone,
I recently started to experiment a bit with my newish AMD X2 3800 on an MSI Neo2 Plat (2 X 1GiG OCZ Pc3200 and BFG6800GT and Antec550PS). I had it running at stock for a few weeks and then started some basic OC'ing. It runs just fine at 2300mhz instead of stock -- in other words 230Mhz X 10 and HT of 4. I clock my RAM down usng the divider to 166 so really it's actually running under it's rated PX3200 spec. Anyhow I benchmarked before and afer using 3Dmark 2005. What is really weird is that I get like 4560 with stock speeds and then 4590 or just over 4600 with an OC to 2300Mhz. It's really not a huge increase in performance but that could be for the RAM decrease in speed.

I then read, thanks to this site that folks are lowering the divider of their CPU an upping the bus speed. I thought this was interesting as I had noted that if I keep my multiplier at 10X and try to go to 250 -- I realy need to start raising the voltage and it does have some stability issues with my limited knowledge and testing and temps go up. Anyhow for fun I dropped the multiplier to X9 and raised the CPU speed from the 230 to 250 (leaving HT at 4X). That brought the total speed to 2250 Mhz which in total is actually LOWER than the 2300mhz I had running before. I kept the RAM at 166 divider which actually clocks it at just over 200Mhz (so that was a bonus). Anyhow I benchmarked it and BAM 4900. Can someone explain how this works? how the hell did I get a better benchmark with a lower total speed? Are AMD's that sensitive to bus speeds? I have not even stretched this.. my temps did not go up and my volatge is stock at these speeds!

Can someone tell me if 9X250 is a bigger strain than 10X230 on my system? Since I am running my CPU at 250 instead of the stock 200 is this requiring more juice and thus more heat is produced or is it offset by the reduction in the multiplier to 9X. I am totally lost now.. sigh.

thanks
Bob

 

[Leper Messiah]

a 230 MHz HTT speed with 166 ram divider is giving you a 190MHz RAM speed, where as 250 is giving you a 210 or MHz RAM speed. My guess would be that 10% or so increase in RAM speed is more than enough to balance out the slightly lesser CPU speed.

Next, try these settings: 250x10, 1.4vcore, 3x HTT, 166 RAM divider.

 

[kamranziadar]

Originally posted by: Leper Messiah
a 230 MHz HTT speed with 166 ram divider is giving you a 190MHz RAM speed, where as 250 is giving you a 210 or MHz RAM speed. My guess would be that 10% or so increase in RAM speed is more than enough to balance out the slightly lesser CPU speed.

Next, try these settings: 250x10, 1.4vcore, 3x HTT, 166 RAM divider.

ditto

 

[BoboKatt]

Thanks for the suggestion -- I will for sure try that and compare vs the X9 multiplier but if I may ask -- why the 3HT? If I am using 250 X 10 the 4HT would still keep me at the 1000 top... I always thought to try and keep it under 1000 or close to it. Are we doing that to further help stability? Can you safely go over 1000?

 

[stevty2889]

I most certainly wouldn't judge my performance increases by using a synthetic benchmark like 3dmark05. 3dmark03 and 05 are not as drasticly affected by the CPU as 3dmark01 is anyway. Run some real world programs and you'll see the improvements.

 

[Leper Messiah]

Originally posted by: stevty2889
I most certainly wouldn't judge my performance increases by using a synthetic benchmark like 3dmark05. 3dmark03 and 05 and as drasticly affected by the CPU as 3dmark01 is anyway. Run some real world programs and you'll see the improvements.

05 should be more GPU bound than CPU bound, but you cannot deny a 10% increase in FSB is better than a -2 % in CPU speed.

Its very hard to actually saturate the HTT bus, even with dual core, see no performance decrease going from 3x to 4x with mine at 10x260.

 

[stevty2889]

argh, I need to stop typing while half asleep, I meant to say 3dmark03 and 05 ARE NOT affected much by CPU speed, like you said they are my GPU bound.