AMD X2 Processors - hotter than single-core?

Rory Buszka · Post by **Rory Buszka** » Sun Jan 15, 2006 10:28 am

I'm looking at cooling an AMD Athlon X2 4200+ with a Thermalright XP-90 and some kind of quiet 92mm fan on it. Perhaps a L1BX panaflo or a Delta tri-blade fan from Sidewinder, on a channel of an MCubed T-Balancer. Does this sound reasonable or do you think that the fan will constantly run fast? At issue here seems to be the question: do AMD's dual-core processors have significantly increased or excessive thermal output when compared to a single-core processor (i.e. a dual-core 3800+ vs a single-core 3800+)?

Hellspawn · Post by **Hellspawn** » Sun Jan 15, 2006 10:48 am

Well, having had both, I found that a 3800 x2 versus a 4000+ amd , the 3800 x2 ran maybe 5c warmer both idle and loaded. Still would idle around 88-90f with the Ninja, like the 4000+ single core.

You are running two cores, but nothing near double the heat output from my experience.

miTchy · Post by **miTchy** » Thu Jan 26, 2006 2:54 am

i used to have a 3200+ winchester and found that X2 3800+ runs a little cooler

McBanjo · Post by **McBanjo** » Thu Jan 26, 2006 4:21 am

Acctually no, atleast not on the +3800. Both generate 89W of heat.
Got to say I'm suprised tho. Generaly a dualcore put out more heat.

Single-cores put out somewhere between 67-89W depending on model while dual-cores are between 89-110W

Tibors · Post by **Tibors** » Thu Jan 26, 2006 4:48 am

McBanjo,
It looks like the numbers you quote are the TDP numbers from AMD. If you look around in these forums and other places on the web, then you'll find they have no real relationship with the actual power consumption of the chips.

stupid · Post by **stupid** » Thu Jan 26, 2006 8:53 am

TDP numbers provided by AMD are typicially higher than the actual heat the CPU will dissappate. Those TDP numbers represents the worst case scenario where the CPU is operating under full load for a prolong period of time.

Intel's TDP numbers are different. They represent moderate to high CPU load of 75% for a prolong period of time.

Officially the Thermalright is only rated up to the Athlon 64 3200+. My advice would be run the fan at full speed, note the temperature of the CPU after running something like CPUBurn for 5 minutes. If it's seems resonable continue to run for another 5 or 10 minutes just in case the CPU has not reached it's maximum temp.

If you are comfortable with the temp, then lower the fan speed a little bit and check the temp after 5 or 10 minutes of CPUBrun. Continue to do this until your are comfortable with the noise, or the temperature is too high for yor liking.

Too much work? Then I suggest getting a HSF that is rated for at least the A64 X2 4200+.

quikkie · Post by **quikkie** » Thu Jan 26, 2006 8:59 am

My rig stays quiet (as far as I am concerned) no matter how hard I push it. The heatsink you have is better than the one I have according to the reviews published here. Since the highest temp I have seen is 25C over ambient temp with the max fan speed of 1200rpm your rig should stay a lot cooler and a lot quieter than mine.

-Quikkie

ronrem · Post by **ronrem** » Fri Jan 27, 2006 2:41 am

Why an XP90? The XP 120 is more efficient,and the Ninja is even more so. Some do run X2's passive with a Ninja,with a nearby case exhaust. Others attach a 120mm at 500-700 rpm. More powerful procs if all 90nm chips,will run hotter AMD's official specs are very general. In reality,a 3000 Venice will run cooler + less watts than a 3500,but AMD lists one TDP for the whole Venice series. It would be interesting to see a chart of real world relative heat covering the AMD 64 stuff from palermo's up through the x2's.

frostedflakes · Post by **frostedflakes** » Fri Jan 27, 2006 7:40 am

I recently upgraded from a 3200+ Venice @ 1.23V to an X2 3800+ at 1.23V. Idle is only a few degrees higher and load with two instances of Prime95 is 10*C higher.

McBanjo · Post by **McBanjo** » Fri Jan 27, 2006 8:45 am

Tibors wrote:McBanjo,
It looks like the numbers you quote are the TDP numbers from AMD. If you look around in these forums and other places on the web, then you'll find they have no real relationship with the actual power consumption of the chips.

Eh no? That's heat, not power

stupid wrote:TDP numbers provided by AMD are typicially higher than the actual heat the CPU will dissappate. Those TDP numbers represents the worst case scenario where the CPU is operating under full load for a prolong period of time.

Yep, 89W doesn't meen it's always 89W but 0-89W. 75% isn't really any usefull since you want to be sure the cooler can handle the cpu even in worst case scenario.
75% is probibly more realistic tho what a normal user generally max hits.

jaganath · Post by **jaganath** » Fri Jan 27, 2006 8:58 am

Eh no? That's heat, not power

Don't most modern CPU's emit like 90% of their power draw as heat? For example a P4 Prescott can be used as a particularly efficient space heater.

chirs · Post by **chirs** » Fri Jan 27, 2006 9:17 am

jaganath wrote:
Don't most modern CPU's emit like 90% of their power draw as heat?

Actually, *all* cpus emit very close to 100% of their power draw as heat.

Tibors · Post by **Tibors** » Fri Jan 27, 2006 9:25 am

McBanjo,
You obviously didn't do the looking around I advised you to do. The TDP numbers are absolute and complete bogus. It is physically impossible that the Winchester core generates the same amount of heat for all the different MHz variations that were availlable. Still that was what the TDP numbers were saying. And as other people already pointed out the difference between the power consumed and the heat emited by a CPU is negligable.

Rory Buszka · Post by **Rory Buszka** » Fri Jan 27, 2006 9:34 am

I'm considering the XP90 because it's nice and cheap, and it shouldn't be too hard to get a 92mm fan to run quietly. I'm planning on "auditioning" four 92mm fans - the Nexus 92mm, the Panaflo L1BX 92mm, the Delta tri-blade fans from Sidewinder, and the Akasa Amber Series 92mm.

Erssa · Post by **Erssa** » Fri Jan 27, 2006 10:01 am

Before you buy the XP-90, read this thread. The new stock cooler of dual cores seems to perform really well. Check it's performance before you buy the heatsink. You may find it's performance well enough and they the only thing you need at most is a fan swap.

Edit: just to summarize the madshrimps article, which can be found from that thread. When XP-90 and AMDs new 4-heatpipe stock heatsinks were both tested with the same stock fan that came with amd cooler, their temperatures were on par! Test was run with dual core opteron 165 overclocked to 2.4 and 2.6ghz and running dual prime95 stable...