AMD 4850e as cruncher
4 Aug 2008 18:06:32 UTC
Topic 193800
(moderation:
Hi all!
I wanted to replace a legacy AMD Athlon XP with something more recent from AMD, not too power hungry and for a limited budget. So I got an AMD Athlon X2 4850e, which is based on the "Brisbane" 65nm (dual)core, runs at 2.5 GHz and has a TDP of 45 W.
Now, what makes me wonder is the core voltage. It is spec'ed as "1.15 / 1.2 / 1.25 V" (yes, three voltages). Those do not describe the Cool'n'Quiet voltage range, tho, as the minimum voltage at lower clock speeds can be as low as 1V . So....why three voltages?
In one forum I read this is "minimum, typical, and maximum voltage", but .... which one should be selected in BIOS? And for which one is the TDP of 45 W valid?
Needless to say I'm now trying the lowest of the three settings, 1.15V, seems to work fine so far.
(As for crunching...well, as expected, this K8 era chip won't come anywhere near a Core2Duo, but the 4850e is quite cheap and the power consumption is reasonable for its performance. )
CU
Bikeman
AMD 4850e as cruncher
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I hope that you bought a good CPU cooler for it. A few months ago, I bought a Brisbane 5200+ model that came with a totally inadequate cooler. It's only a 65 Watt part, but the cooler is so bad, that I have to run it way underclocked to keep it from overheating. (Hopefully, someday, I can get around to ordering a decent cooler.)
Hmmm... Well, without
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Hmmm...
Well, without actually going and looking at the AMD spec sheet...
Typically, the high and low values are the rated maximums for voltage for that model number. The middle (typical) would be the recommended (nominal) operating voltage for the device. Generally if you read the notes, they measure things like TDP when operating the device at the nominal voltage, so my guess is setting the BIOS for 1.2 V (or let it select it automatically) would get the closest to the rated 45 W rating at full load.
Of course in this day and age where the marketing guys get involved with their input as to what the technical specs should be, it's always wise to make sure you read all those notes and disclaimers carefully. ;-)
Alinator
I'm using AMD 4850e, I've
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I'm using AMD 4850e, I've even overclocked it, it works great with stock cooler. Mine works on 1.25V.
http://einsteinathome.org/host/1426025/tasks
As you noted, the Brisbane
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As you noted, the Brisbane 5200+ is a 65 watt rated CPU -- and puts out more heat.
That said, the stock coolers on the AMD's tend to be lame. I typically replace them with 3rd party coolers (Arctic Cooler mostly). Though I haven't seen problems with the 65 watt AMD's and overheating even with the stock coolers -- as long as they are not overclocked -- even when running BOINC which full loads the CPU all the time. Then again, I take care that the boxes they are running in are not mini-towers and have adequate fans (not just the power supply fan), AND I don't load the workstations up with heat generating video cards.
I have even gotten away using the stock AMD fan on the entry level Phenom tri core and running BOINC -- it stays under 50C as well.
That being said, if one goes with the higher speed AMD dual cores, or overclocks them (I've run the Black Edition 5000 at 15x -- the equivalent of a 6000), then you need a good 3rd party fan. I am guessing that you would REALLY need solid cooling at the top end -- the 125W X2, or 125W or 140W X4 processors. I have avoided them.
Of course gamers really need airplane hanger cooling -- running 125W or 140W quad cores and two high power video cards -- that generates a LOT of heat. Glad that I don't have to support folks who do that.
Thanks all. I got mine as
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Thanks all.
I got mine as a boxed version complete with fan. I'm not going to overclock it, and CPU temp seems to stay in the low 40s (°C) at max load...perhaps no wonder with a TDP of only 45 W. I think the cooling will be fine, even tho I just have the CPU and PSU fans, no extra case fan.
My BIOS auto-selected 1.25 V, and supplied a measured (according to BIOS) 1,27V. As power consumption is proportional to voltage squared, I'd rather prefer 1,15 V :-).
The fastest S5R3 result I've seen so far on it took about 18400 sec.
CU
Bikeman
RE: I'm using AMD 4850e,
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Oh yes, this one's much faster than mine at stock speed. 2.8 GHz or above?
CU
Bikeman
RE: That said, the stock
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My data is obviously "rusty", considering it is based on Socket 939, but typically AMD provided higher end coolers on the Opteron line than they did on the consumer-based products, even the X2. The FX line might've had a decent cooler. Not sure...
As for 3rd party, Thermalright tends to get very good reviews. I have the SI-120 on my 3700+...
RE: Now, what makes me
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AMD produces the same CPUs with more voltages.
Probably the lower voltage version has better under/overclocking potential.
RE: Oh yes, this one's
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Yes it works on 2.85Ghz.My uptime is 20days and the last time I had to restart was because of some update requested it, that is, it works perfectly stable.
RE: My data is obviously
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Higher end 939 x2's had a big copper HSF with heat pipes instead of the puny alluminum lump.