AMD 780G - The Three Amigos and a 9850BE
by Gary Key on April 30, 2008 6:00 PM EST- Posted in
- Motherboards
It is time to introduce the fine print and disclaimers when using these boards with a Phenom 9850BE. As a recap, the critical aspect of running a 9850BE at stock speeds on current 780G products centers on the cooling of the PWM circuitry. Each and every manufacturer along with AMD agreed that cooling the MOSFETS properly was critical to the successful operation of the board at stock or overclocked speeds with the 9850BE - and to some degree, the 6400+ X2. This is based on the board manufacturer utilizing a properly developed power delivery system that is designed to handle the 125W TDP processors and in the future, the upcoming 140W TDP Phenoms.
We still do not think the majority of users who purchase these boards will end up installing AMD’s top of the line CPU. Personally, we would not install a Phenom 9850BE or 9750 retail unit in these boards considering the vast majority of applications these boards will see can get by fine on an Athlon 4850e or Phenom 8450. However, for those who wish to continue down this path we have a few suggestions.
Everyone probably knows the old saying about the three rules of real estate, location – location – location. It holds true with our board samples only replace location with airflow. We found additional airflow around the PWM/MOSFET area was critical when utilizing the stock retail fan/heatsink in our Silverstone SG03 case. We installed a secondary 120mm fan that provided enough airflow over the board to ensure stable operation under our load scenarios. While that was acceptable for the most part, it did increase noise levels a little more than we expected. In the end, we ended up replacing the stock case fan with one that offered slightly higher airflow with only a small penalty in acoustic levels.
Our other solution was to replace the stock heatsink unit with a radial design that improved airflow around the CPU area to the point where the boards did not experience thermal related shutdowns or catastrophic failure when we played “Pop goes the MOSFET”. We found that increasing our case airflow provided temperature drops in the PWM/MOSFET area about 5~11C better than the radial fan design. However, our processor temperature dropped about 3C at idle and averaged 9C lower at load when compared to the stock heatsink. Additionally, acoustic levels dropped on average about 4dB(A) with the radial fan setup.
Utilizing our standard test bed components with the 9850BE, we ran our Jetway, ASRock, and Gigabyte boards over 102 hours each with a combination of OCCT, Microsoft Flight Simulator X, and PCMark Vantage benchmark loops. We did this with the case fan modification first and then again with the Thermaltake RubyOrb installed. We did not have any thermal related failures or shutdowns under load as we had experienced with just the retail heatsink installed in previous testing. We also overclocked the 9850BE slightly to 2.7GHz and ran an additional 48-hour combination of OCCT and PCMark Vantage loops without a problem utilizing the two front-mounted case fans and retail heatsink.
Our Biostar and Sapphire boards both passed the 102-hour test. We did experience thermal related shutdowns with OCCT around the 40-minute mark on both boards with just the retail heatsink and standard case configuration. This also occurred around the two-hour mark with PCMark Vantage. In fact, we had Biostar send us another board after a bad overclocking experience (our fault for trying) with the 9850BE on an open test bed setup. We did not test either board in an overclocked condition but feel safe in their capabilities to run the 9850BE at stock settings with proper cooling.
Our results just reiterate that adequate airflow is required when utilizing a 125W TDP processor on these particular boards that are qualified by the manufacturers to work with the Phenom 9850BE or retail 9750 (OEM version is rated at 95W TDP) processors. At this time, AMD has not qualified the Jetway, ASRock, Gigabyte, Biostar, or Sapphire 780G boards to operate properly with the 125W TDP processors. Please keep this in mind when considering one of these combinations as only the manufacturer has stated compliance or in the case of Biostar and Sapphire, implied it. That said, we have finally completed our testing and will have performance results from these boards and others in the near future.
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R3MF - Thursday, May 1, 2008 - link
the 9850 costs a mere £150, about one fifth the price of the top end consumer chip from intel.i have just built a Sugo03 gaming machine using the famous Gigabyte G33 DSR2 board and a £175 Q6700 chip.
i wanted to get an AMD system but when i am blowing £1300 on a new PC why on earth would i buy a cheap rubbish motherboard that is likely to fry at a moments notice?
mczak - Thursday, May 1, 2008 - link
Ok, so the mosfets don't instantly blow up - good. I wonder though about long-term usage, any chance they'll still work after a year or two if they are operated so close at their limit?hoohoo - Thursday, May 1, 2008 - link
I run an Opteron 1220 on a 690G uATX board with aan 8800GT in a small Silverstone case. I had to get aftermarket coolers but it works fine - stock or O/C to ~ 3GHz. Civ 2 to Crysis, Cell processor simulator, hand coded threaded C apps, image processing software.What are those apps you speak of? Lots of people like microATX because they do not want some maximum tower plastic-and-flashing-lights encrusted behemoth in their home. And let's not mention the wonderful price of your 'serious' boards!
bradley - Thursday, May 1, 2008 - link
You make an extremely valid point about micro-ATX board builders having different considerations and allowances, probably centering around lowering cost, power usage, and decreasing size. Running high-powered cpus without ample cooling on anything but a regular ATX might not be a good idea. I'd be curious how disabling on-board video might affect 780G real-world stability and compatibility though.JarredWalton - Thursday, May 1, 2008 - link
But you are clearly not a typical user of computers or mATX boards. The vast majority of users will surf the internet, watch some movies, listen to music, and run office applications. They might also do some image manipulation, but not for a lot of people. Using just the IGP, we can pretty much rule out games as being a primary consideration... which also rules out Cell simulations most likely. The number of people that do C/[insert favorite programming language] coding is also likely less than 1% when you look at the whole market.Just because you in particular do something with computers doesn't mean you're in the vast majority. Not that that's a bad thing. I'm quite sure I don't meet that qualification either.
hoohoo - Thursday, May 1, 2008 - link
That is exactly my point: I do not think I am especially untypical. The marketers, and popular prejudice like yours, would have it that expensive and large ATX boards and cases are the proper place to use higher TDP CPUs. I say that is incorrect and arbitrary on your part because many people care as much about the form factor as the horsepower - and definitely want the horsepower.The uATX 780G boards all come with one PCIe 16x slot: I'd say most people are not going to buy 2 or 3 video cards. They want one fast GPU and fast processor and IMHO most people do not want massive cases (at least after they've had to live with they first one). Therefore uATX.
Heat need not be an issue with uATX. The boards in question ought to have been built with decent power regulators (or that they were not made plain), not built on the assumption that only weak CPUs will be used.
The desire of marketers to sell expensive ATX boards requires no comment I think.
FWIW, the Cell simulator does not care about graphics capability. I've got the 8800GT for games.
An aside: Someone below commented that he doesn't really want SB600. I can only agree, it is very hot and needs a little fan all of it's own on my board. 780G is an excellent chip and the new SB being paired with it on most of these uATX boards is superior to SB600. AFAIK there aren't even any ATX boards being made with the new SB!
docmilo - Thursday, May 1, 2008 - link
As a typical user of one of these boards, the Asus model which is not listed here, I am currently running the 9600 Phenom. I run it in a Q-Pack case and have no heating issues at all. I would love to be able to drop in a 9850BE for converting my tv recorded shows to MPG4, editing home videos and have a higher speed to do the occasional game. Prior to this I was running a 6000+ on a 690G board and it would get way too hot. My 6000+ was faster at converting the video but at 100% cpu usage there was always some lag if I wished to do something else and the cpu would run at 60+ degrees. Converting now rarly goes above 50% cpu utilization and 45 degrees.m3rdpwr - Thursday, May 1, 2008 - link
I don't think it's un-realistic for someone to run a 9750 or 9850 CPU on these boards.I'm not really a gamer.
However, I do some photo editing that my current AMD system single core doesn't handle well. The onboard video would probably hand this just fine.
The Gigabyte board is exactly what I want, but I don't want to buy it based on a what if.
I don't want a 790FX board because of the SB600.
(I would prefer 790FX/SB700/SB750.)
Looks like for peace of mind, I need to wait for the 790GX/SB750 board to start appearing...
-Mario
just4U - Thursday, May 1, 2008 - link
The problem I have is I'd have gone right ahead and grabbed a 9750 not even thinking that it was a 125 one... and paired it up with the 780G but after knowning what I know know I can't just up and do that... The people I'd build those for would require around 3 years of use out of them and I wouldn't want the damn thing to magically die sometime after it's set up.996GT2 - Thursday, May 1, 2008 - link
Those bottom 3 fins get very little to no airflow to them, so the MOSFETs aren't cooled well at all. In my experience with the Freezer 64 Pro on a MSI K9N Platinum, the heatsinks over the MOSFETs get quite warm since only a tiny bit of air is being blown at them by the Freezer 64. You also have to run the Freezer at full speed to be able to feel the airflow behind it, and doing so makes it moderately loud.I would suggest getting a heatsink that blows directly over the board, such as a Zalman CNPS8000 or a Cooler Master Gemini II. Those would help cool the board as a whole, not just the CPU...however, coolers blowing up-down aren't as effective as heatpipe tower coolers that blow air from the front of the case to the back.