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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helldrell666 - Wednesday, July 23, 2008 - link
I dont why, but when it comes to AMDs products, i get the worst scores from anandtech reviews.Maybe,Charlie demirjian was right after all, anandtech hate AMD.
I got the worst 4870 results from anandtech.
At tomshardware and techreport, the 4870 did much better.
In your previous review,the 9850BE reached 3.3GHz on 1.38v.
Do you hate AMD anandtech?
cdbular - Wednesday, July 23, 2008 - link
"Do you hate AMD anandtech?"No they don't, but Intel maintains this WEB, Just look at the ads in the page...
ZootyGray - Thursday, July 24, 2008 - link
Ads? What ads?Dude - you would enjoy FIREFOX w 'Ad Blocker' - there are no ads :)
helldrell666 - Wednesday, July 23, 2008 - link
Im tired of shintel and nshitia. All this propaganda to destroy the image of AMd/ATI.But,the time will coe when DAAMIT will rape them all.Its just a matter of time.
jdizzle1337 - Wednesday, July 23, 2008 - link
Too bad AMD hasn't worked itself back to having the credibility to create "rumors".Phenom round 1 was 100% hype and obsolete upon release. Sorry AMD you are on believe it when i see it status.
wingless - Wednesday, July 23, 2008 - link
Did you not read the review? The SB750 works as advertised in a big way.Guuts - Thursday, July 24, 2008 - link
AMD actually advertised something?? :-pHarbmike99 - Wednesday, July 23, 2008 - link
Yea I know the CPU has a bug. I have never seen it I have the patch turn off. But will this new SB help it too. I have not overclocked it (too much just once to see if I could get 2.5, and I did) because I am stil useing a older AM2 board, and I am planing to buy a new board and give the old board and X2 cpu to a freind.So will it help?
I would love to get to 3 ghz. I have seen some say on fourms they got that. What so you guys think?
jay2o01 - Wednesday, July 23, 2008 - link
Anyone else intersted how a Phenom 9850 performs at 3.0 ghz with a 2.4ghz+ NB? What kind of improvements would this yield over the stock speeds?Zisyncmon - Wednesday, July 23, 2008 - link
Yeah I'd agree, it will take some benchmarking to really see what improvement this OC'ing does to performance, but I am sure they are busy finding good settings to test at.