Stuck at 4GHz with the Phenom II X4 940...
by Gary Key on January 29, 2009 12:16 PM EST- Posted in
- Gary's First Looks
We have been testing the overclocking capabilities of the Phenom II X4 940 (seriously, who names these products?) for an AMD roundup and have hit the proverbial brick wall. It has not been for the lack of trying or even using a stellar motherboard to test these processors. The motherboard choices have ranged from some wicked little 790GX overclockers from ASRock, Gigabyte, and DFI to the flagship 790FX products from ASUS, MSI, and Foxconn. We even tried a few NVIDIA 780a based motherboards along with a slew of newly arrived AM3 compatible boards. We changed cooling, processors, video cards, disk drives, memory, and tried every available voltage setting. It did not matter. We could not break the 4GHz barrier and still complete our benchmark test suite.
The only commonality between our 30 different setups is the operating system. We recently standardized on Vista Ultimate 64 SP1 for testing. Granted, we had this same problem when our 940 engineering samples first arrived and we asked AMD about it. However, AMD never did get to the bottom of it before the launch date. We thought our results might change with retail processors. Alas, they did not. We have four retail CPUs, three with 0850 lot codes and one from the 0849 batch that all behave the same way under Vista 64.
Our final benchmark stable clock speed is 3.955GHz reached via a 17.5 core multiplier and a 226 HTT setting on our . This required a 1.6V VCore setting (with droop, real voltage is around 1.585V) on our DFI DK 790FXB-M2RSH motherboard. Memory speed is DDR2-1205 at 5-5-5-18 timings with VDimm at 2.060V. This is the setting we will utilize in our upcoming roundups. We mention it now as our Core i7 920 will operate at 4GHz and Q9550 at 4.25GHz, not exactly fair, but we are looking at platform capabilities on air cooling in the overclocked sections. As one would say, it what it is.
What is really strange is the behavior of the OS and Phenom II X4 940 at the 4GHz mark. We actually have 3.990GHz (19x210) stable for all tests except Crysis and the PCMark Vantage TV/Movies test suite. With that in mind, a simple change to 19x211 for a 4.009GHz clock speed results in the majority of our tests failing. We sometimes have trouble even entering Vista at 19x211, while 19x210 is about 97% benchmark stable. We have tried every possible combination (20x200, memory at DDR2-800, 1GHz NB speed, etc.) and even chilled the processor down to 16C and raised processor voltages above 1.7, nothing worked above 4GHz.
At least under Vista 64 as Vista 32 was much different. The settings mentioned earlier allowed us to reach a stable 4.275GHz (19x225) with the same components. However, we are not utilizing Vista 32 in testing anymore, especially considering our standard benchmarks are completed with 4GB and 8GB configurations on the DDR2 platforms. As such, it appears at this time that any overclocking comparisons will be limited to under 4GHz on the AM2+ and AM3 platforms. We have addressed this problem with AMD again and hopefully an answer is forthcoming. In the meantime, we figured out a way to get a screenshot above 4GHz before we received the standard BSOD routine. At least it is a consolation prize at this point.
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WillR - Sunday, February 1, 2009 - link
Could you please not screw the English language so much?Also, i7 is a more energy efficient proc than Phenom II or Core 2. Unless all you do with your computer is "oh, l33t 1 has mor fps!" then you have to take processing time into account as well as power draw. Core i7 runs hot, but who cares if it's stable at higher temps? My only problem with i7 right now is the related hardware's price. It's why I just purchased a 940 yesterday. Price/performance of C2Q and PII are similar, Socket T doesn't appear to have much life left in it, and we all benefit from AMD staying in business.
Damn, fanboys on either side are annoying.
BlueBlazer - Saturday, January 31, 2009 - link
Retail PhII have problems getting pass 3.9GHz FULLY STABLE on air cooling..Go back to your FantasyZone...
0vercl0ck - Saturday, January 31, 2009 - link
Isn't it really strange?Team Finland (SF3D & Sampsa) reached 6435.62 MHz with an AMD Phenom II ES (45 nm).
AMD Phenom II
Windows Vista Ultimate Edition SP1 (Build 6001)
CPU Arch : 1 CPU - 4 Cores - 4 Threads
CPU PSN : AMD Engineering Sample (ES)
CPU EXT : MMX(+) 3DNow!(+) SSE SSE2 SSE3 SSE4A x86-64
CPUID : F.4.2 / Extended : 10.4
CPU Cache : L1 : 4 x 64 / 4 x 64 KB - L2 : 4 x 512 KB
CPU Cache : L3 : 6144 KB
Core : Deneb (45 nm) / Stepping : RB-C2
Freq : 6435.62 MHz (286.03 * 22.5)
MB Brand : DFI
MB Model : LP DK 790FXB-M2RS
NB : AMD 790FX rev 00
SB : ATI SB750 rev 00
GPU Type : ATI Radeon HD 4870 X2
GPU Clocks : Core 507 MHz / RAM 500 MHz
DirectX Version : 10.0
RAM : 2048 MB DDR2 Dual Channel
RAM Speed : 572.1 MHz (1:2) @ 5-5-5-18
Slot 1 : 1024MB (PC2-5300)
Slot 1 Manufacturer : OCZ
Slot 2 : 1024MB (PC2-5300)
Slot 2 Manufacturer : OCZ
BlueBlazer - Saturday, January 31, 2009 - link
Those samples were given to them by AMD directly, in other words...THEY WERE CHERRY PICKED
Go browse XS and check how retail PhII actually overclock ON AIR is like...
MANY CAN'T GET PASS 3.9GHz FULLY STABLE... DESPITE EXTREMELY HIGH VCORE...
0vercl0ck - Saturday, January 31, 2009 - link
The standard BSOD routine is unrelated to CPU overclocking!Set your RAM to normal stable performance, than overclock CPU!
Once you got crashes as the result of overclocking CPU, lower the setting to previos stable, and ONLY than overclock the RAM!
Your standard BSOD routine is related to wrong memory setting and have nothing to do with CPU!
"Memory speed is DDR2-1205 at 5-5-5-18 timings with VDimm at 2.060V"
When overclocking first set memory to standard setting, overclock CPU, than play with memory timing!
"Set the memory to 5-5-5-12, at optimal voltage, than overclock.66
"What is really strange is the behavior of the OS and Phenom II X4 940 at the 4GHz mark. We actually have 3.990GHz (19x210) stable for all tests except Crysis and the PCMark Vantage TV/Movies test suite. With that in mind, a simple change to 19x211 for a 4.009GHz clock speed results in the majority of our tests failing. We sometimes have trouble even entering Vista at 19x211, while 19x210 is about 97% benchmark stable. We have tried every possible combination (20x200, memory at DDR2-800, 1GHz NB speed, etc.) and even chilled the processor down to 16C and raised processor voltages above 1.7, nothing worked above 4GHz."
0vercl0ck - Saturday, January 31, 2009 - link
Aftere reading all the posts above it is clear that the great majority of the posts, except 2, is made by egzperts!so what is the definition of an expert?
An asshole out of town?
Iyt is clear that thge attempt of this article more likely was to prove that AMD can not handle more than 4.o giigs.
The truth however is that your overclockers know shit!
http://valid.canardpc.com/show_oc.php?id=481726">http://valid.canardpc.com/show_oc.php?id=481726
So what is wrong with you guys?
Shitheads not overclockers!
0vercl0ck - Saturday, January 31, 2009 - link
the MoBo was:DFI LP DK 790FXB-M2RS (AMD 790FX rev 00) - RAM : OCZ 2048 MB
http://valid.canardpc.com/show_oc.php?id=483004">http://valid.canardpc.com/show_oc.php?id=483004
http://valid.canardpc.com/show_oc.php?id=481726">http://valid.canardpc.com/show_oc.php?id=481726
http://valid.canardpc.com/records.php">http://valid.canardpc.com/records.php
ghostfaceChillah - Friday, January 30, 2009 - link
May I point you to some results that differ from your conclusion?http://www.overclock.net/amd-cpus/442493-phenom-ii...">http://www.overclock.net/amd-cpus/44249...enom-ii-...
RobberBaron - Friday, January 30, 2009 - link
Definitely pop in another 64 bit OS to verify that this isnt a hardware limitation instead of an ugly Vista 64 problem.Ratman6161 - Friday, January 30, 2009 - link
I know its easier to focus on the 940 BE with its unlocked multipliers. But for a lot of us the point of overclocking is to buy a cheaper part and make it as fast or faster than the more expensive top of the line part. So I think a lot of us would be more interested in what could be done with an x4 920.