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4850 Crossfire

M

Modular

Diamond Member
I'm looking to double up my current 4850 and go the Crossfire route, but I'm not sure if the performance increase will be worth it over going with a 6850 instead. Here's my specs:

1680 x 1050 Monitor
Phenom II X4 920 @ stock
4GB ram
Earthwatts 500watter
790GX mobo

I've checked the web for reviews, and can't really seem to find anything recent, so if people with the 4850 in Crossfire can chime in as to their experience, that would be awesome.

Thanks!

Edit: The second 4850 is only going to cost $40-50. So take that into account as well.
 
If you have the 1GB version then it would probably be worth it. But if you have the 512MB version then I think a single 6870 (or overclocked 6850) would provide a better option.
 
the max 12v load on the old Earthwatts 500 watt psu is 408 watts. with a 4850 crossfire setup you would really be stressing that especially if you did any overclocking. and as already mentioned if thats a 512mb then its not worth the hassle anyway.
 
toyota said:
the max 12v load on the old Earthwatts 500 watt psu is 408 watts. with a 4850 crossfire setup you would really be stressing that especially if you did any overclocking. and as already mentioned if thats a 512mb then its not worth the hassle anyway.
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:thumbsup:

I wouldn't do 4850x2 on a 500W PSU either.
 
3DVagabond said:
:thumbsup:

I wouldn't do 4850x2 on a 500W PSU either.
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I Second that. If you had the power to run two 4850 512's I would do it for a little bit. What's $40 bucks to have some good ole crossfire fun for a little while. Also at 1680X1050 512mb could play most games with max settings - just no AA enabled.
 
toyota said:
the max 12v load on the old Earthwatts 500 watt psu is 408 watts.
Click to expand...
A 4850 is 100W and less. The Phenom 920 is 75W and less. Platform is 50W and less. You do that math; he would be quite safe. The Eartwatts supplies two 6-pin connectors and that's all he would need.
 
cusideabelincoln said:
A 4850 is 100W and less. The Phenom 920 is 75W and less. Platform is 50W and less. You do that math; he would be quite safe. The Eartwatts supplies two 6-pin connectors and that's all he would need.
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that system could easily pull around 350 watts under full load even with no overclocking. and remember if his psu is a bit old then its not going to make the 408 watts on the 12v anyway. so yes it will be stressing it quite a bit.
 
happy medium said:
Right, I've seen this psu running 2 gtx260's. It will do 2 4850's easy.
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just because someone does something doesnt make it a good idea. even my system with an E8500 and single gtx260 pulls over 325 watts at the wall under full load. another gtx260 would absolutely push me over 400 watts even at the psu.
 
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toyota said:
just because someone does something doesnt make it a good idea. even my system with an E8500 and single gtx260 pulls over 325 watts at the wall under full load. another gtx260 would absolutely push me over 400 watts even at the psu.
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GTX 260 is considerably more power hungry than a 4850:
http://forums.anandtech.com/showthread.php?t=2126448

Why don't you define "full load". Is that OCCT's combined test? Furmark + Prime? A game? Full load can have a different meaning.

325W at the wall is only 275W for the system, assuming at that load your PSU is 85% efficient. Add at most 50W for dual 4850s compared to a single GTX260, and he's quite safe under your "full load".

And you are blowing the "aging" thing out of proportion here. You might have a point if the proposed system was at the limits of the PSU under a typical load, but under a gaming load dual 4850s would be safely under the PSU's limit.
 
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cusideabelincoln said:
GTX 260 is considerably more power hungry than a 4850:
http://forums.anandtech.com/showthread.php?t=2126448

Why don't you define "full load". Is that OCCT's combined test? Furmark + Prime? A game? Full load can have a different meaning.

325W at the wall is 275W for the system, assuming at that load your PSU is 85% efficient.

And you are blowing the "aging" thing out of proportion here. You might have a point if the proposed system was at the limits of the PSU under a typical load, but under a gaming load dual 4850s would be safely under the PSU's limit.
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why take my gtx260 comment out of context? I know it uses more power than a 4850 and my comment was in reply to happy. he was saying someone used gtx260 sli on that psu which would barely be possible if at all.

by full load I was meaning if he was to happen to test in furmark. of course games would typically be lower but that system could easily pull 350 watts. and I dont mean at the wall. even if that psu had 400 watts available that is close to 90% load. so again that is too much stress for long term use IMO. and with any overclocking he would absolutely be pushing that psu too much.
 
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toyota said:
why take my gtx260 comment out of context? I know it uses more power than a 4850 and my comment was in reply to happy. he was saying someone used gtx260 sli on that psu which would barely be possible.

by full load I was meaning if he was to happen to test in furmark. of course games would typically be lower but that system could easily pull 350 watts. and I dont mean at the wall. even if that psu had 400 watts available that is is close to 90% load. so again that is too much stress for long term use IMO. with overclcoking he wouls absoltly be push that psu too much.
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I just used your numbers as a reference that he would still be safe, using your findings on top of numbers from other sites (namely techpowerup and lostcircuits).

And I agree he should not overclock if he happened to go dual GPU. His original post said he was running stock so I assumed he wouldn't really be overclocking.

In either case I still think a single 6850 or 6870, or GTX 460, would be a better overall option, in terms of performance and performance consistency. He will probably pay more, though, as he could get a 4850 on the cheap. So it basically comes down to cost, IMO.
 
cusideabelincoln said:
I just used your numbers as a reference that he would still be safe, using your findings on top of numbers from other sites (namely techpowerup and lostcircuits).

And I agree he should not overclock if he happened to go dual GPU. His original post said he was running stock so I assumed he wouldn't really be overclocking.

In either case I still think a single 6850 or 6870, or GTX 460, would be a better overall option, in terms of performance and performance consistency. He will probably pay more, though, as he could get a 4850 on the cheap. So it basically comes down to cost, IMO.
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yeah I guess without any overclocking he should be fine. I just like to always be on the side of caution and not stress a psu by more than 80-85% of its rated 12v power. this is especially true if the psu has already been used for quite a while.

and I totally agree that he should just go with a single card upgrade and sell his 4850. that would eliminate any crossfire and/or potential power supply issues if he ever overclocks.
 
I'm doing 2x 4850s (512MB) on a 3.5 year old 500W (Silverstone) PSU right now, with no problems at all. I'm on an x3 720 running a mild overclock, and no matter how many CPU/GPU stress tests I've run, I cannot get the thing to draw more than about 300w from the wall. I'm also running at 1680x1050 and while I'm pretty happy with the results, I usually can't totally max everything AND have AA with a totally smooth frame rate.

Cliffs: Haters gonna hate - go ahead and get the second 4850 if you're really only looking to spend a little bit. I think you'll be pretty happy with the results, and if you're not, hey, you're only out $50.
 
i did the second 4890 a few months ago. i am really pleased with the results.

as others have said, i would be wary at first about only 500w, but i think it would be ok as the 4850 is not as power hungry as a 4870 or 4890.

also, dont psu's get more efficient as they approach full load (im thinking eighty percent; no not 80 plus) compared to one running say a forty or fifty percent load?
 
v0id said:
Cliffs: Haters gonna hate - go ahead and get the second 4850 if you're really only looking to spend a little bit. I think you'll be pretty happy with the results, and if you're not, hey, you're only out $50.
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Since when is offering advice or an opinion hating? Toyota stated he wouldn't recommend crossfire with that PSU, and I seconded. Since then others have concurred. The minimum recommended PSU for a single one is 450W. You can do over 150mph on tires that aren't V rated too. It's just not something I would recommend to anyone.
 
Spikesoldier said:
also, dont psu's get more efficient as they approach full load (im thinking eighty percent; no not 80 plus) compared to one running say a forty or fifty percent load?
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The efficiency curve is different for every power supply. From 0% load to some arbitrary load the PSU will get more efficient, since it is pretty inefficient at very light loads. From that peak efficiency point (x%) to 100% load, PSUs typically go down a bit in efficiency - and how far down they drop again differs from PSU to PSU.
 
Thanks for the replies and the PSU discussion. I think I'm going to hold off for now because I like to tweak things and have my current 4850 at 800 core with a voltage boost. I can only imagine what my power draw is with it like that, and what it would be with 2 of them doing that.

Also to be honest, other than Bad Company 2, I can run most games on high settings with 2x aa on this one card. I don't really have the need to upgrade as much as I have the urge to, so I can wait until the 560 is released and see what it does to prices of lower tier video cards. Heck, maybe I'll pick one of those up 🙂
 
Modular said:
Thanks for the replies and the PSU discussion. I think I'm going to hold off for now because I like to tweak things and have my current 4850 at 800 core with a voltage boost. I can only imagine what my power draw is with it like that, and what it would be with 2 of them doing that.

Also to be honest, other than Bad Company 2, I can run most games on high settings with 2x aa on this one card. I don't really have the need to upgrade as much as I have the urge to, so I can wait until the 560 is released and see what it does to prices of lower tier video cards. Heck, maybe I'll pick one of those up 🙂
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Even though your psu would be ok , I believe you made a good decision.
 
I had two 4850's for a long while. I would go crossfire instead of purchasing something new. I upgraded to a 460 and dont notice an increase.
 
I ran a Q6600 @ 3.6 (power hog!), and two GTX 460 1GB cards at 820Mhz, doing F@H on all three, on an EarthWatts 650W PSU. I had to use two PCI-E power splitters to do that, and the PCI-E power cables coming from the PSU got slightly warm, but other than that, it ran for the whole month of Dec.

I'm re-doing my rigs though, and the Q6600 got decommissioned and the GTX460s parted out to my two other desktop rigs, that I'm upgrading with Q9300 CPUs. The first one I did, it OCed from 333 FSB to 400 FSB (2.5 to 3.0) without even touching the vcore. It seems to draw LESS power than the overclocked, overvolted, 65nm dual-core it replaced.
 
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