AMD's SB750: Enabling Higher Phenom Overclocks?
by Gary Key on July 23, 2008 12:00 AM EST- Posted in
- CPUs
Higher Overclocks in Vista 32-bit vs. 64-bit?
In preparation for this article we also wanted to test one more theory: that Phenom overclocks better under 32-bit Vista than 64-bit Vista. The basis for this theory is that the number of active registers increase in 64-bit mode, which creates additional workload routines that leads to increased transistor switching that ends up increasing thermals and loads on the IMC. Well, you get the picture, not exactly a cycle of events that would lead one to believe an already clock starved core design has a chance when moving to a 64-bit environment, well at least Vista 64-bit. In case you're wondering, Intel CPUs seem to overclock the same regardless of OS but just for kicks we tried our 9850 under the two OSes to see how things differed:
| Phenom 9850BE - Highest Core Speed / HT Ref Clock Vista 64 versus Vista 32 |
||||||
| Core Speed | HT Ref Clock | HT Link Speed | North Bridge Speed | Memory Speed | CPU VID | |
| Foxconn A79A-S ACC On - Vista 32 | 3382 | 205 | 2050 | 2255 | 1093 | 1.4750V |
| Foxconn A79A-S ACC On - Vista 64 | 3280 | 205 | 2050 | 2050 | 1093 | 1.4625V |
| . | ||||||
Strangely enough, our highest HT overclock with the 9850BE was bested by 102MHz in core clock speed and a 205MHz improvement in NB speed under 32-bit Vista. It's not a huge advantage, but something we were definitely able to identify and confirm on a variety of settings with several different processors.
| Phenom 9850BE - Highest Core Speed / HT Ref Clock Vista 64 versus Vista 32 |
||||||
| Core Speed | HT Ref Clock | HT Link Speed | North Bridge Speed | Memory Speed | CPU VID | |
| Foxconn A79A-S ACC On - Vista 64 | 3000 | 200 | 2000 | 2200 | 1066 | 1.3500V |
| Foxconn A79A-S ACC On - Vista 32 | 3150 | 210 | 2100 | 2520 | 1120 | 1.3500V |
| . | ||||||
The biggest difference we noticed between the two operating systems and overclocking occurred when we significantly raised our NB speeds and trying to increase HT ref clock with this particular CPU. We just could not run high NB speeds under Vista 64 in the sweet spot for this processor, which is around 3.0GHz at fairly reasonable voltages. We are still testing this phenomenon (pun not intended) as our 9950BE clocks at nearly the same rates under each OS.
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ZootyGray - Friday, July 25, 2008 - link
@ xrayAgree. However we don't know. Are they going to keep it secret? Is it about competition? or proprietary? Is there more to it? Is there a hidden ?thing? in Phenom? Is there "black magic"? Has it all been a deliberate lag behind so that they can come roaring back to life and look like the greatest thing since the resurrection? Look what they did to nvidiot with the 48x0 release. And the new CEO wants to offer more performance. Lots going on here = wow! This has my attention, and I want facts.
My point is that Anandtech is already barking up this same tree - they don't know - they have inquired - and they are reporting known facts - and that is the real food that we have come to eat. More will be revealed. Maybe the answer is the "don't dare mention"; but I doubt that. Maybe a lot of things. It's all exciting to me as AMD makes some noise.
I watch and wait.
eetnoyer - Thursday, July 24, 2008 - link
"error of margin"?I think you meant confirmation, not conformation.
The Preacher - Thursday, July 24, 2008 - link
The clock speed reported by CPU need not tell the whole story. The new system might actually drop a clock cycle here and there and might not increase the CPU performance at all, despite the higher reported frequency.CyberHawk - Thursday, July 24, 2008 - link
What is the product that we dare not mention its name? Mentioned twice in the article.If there is word about Overdrive Utility I guess that it is a new CPU on horizon.
What do you think?
nubie - Thursday, July 24, 2008 - link
I don't think it is a new CPU, in "Final words" they seem to hint it is a new IGP with a lot more performance on tap.If they can storm the market with a 4850 for $200, I am sure that they can integrate something to run today's games at minimum settings on the motherboard and keep it under that price.
luk1999 - Thursday, July 24, 2008 - link
Could you test overclocking on this motherboard with some standard (non-Black Edition) Phenom?dvijaydev46 - Thursday, July 24, 2008 - link
I wish you did at least a few benchmarks and published. I was very curious to see how a phenom performs at 3.5 GHz.MikeODanyurs - Thursday, July 24, 2008 - link
My SB (supposedly SB700) has the same production week and only 2 digits and one letter difference on my Gigabyte GA-MA78GPM-DS2H motherboard. Anyone know if it's the letter or the 2 digit numbers that identify the SB750?http://i172.photobucket.com/albums/w35/IITravel/DS...">http://i172.photobucket.com/albums/w35/IITravel/DS...
imaheadcase - Wednesday, July 23, 2008 - link
Hardly can read pictures.. :POrphanShadow - Wednesday, July 23, 2008 - link
I know the pin link with Phenom chips is what gives them the extra headroom with ACC, but will this also apply to the AM2+ Budapest based Opteron Quads too?