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Radeon HD 7870 with Corsair CX430 V2?

seadrag0n

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Dec 8, 2012
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Hey guys, just two days back I bought new PC with the following config:

Intel Core i3 3220
Gigabyte GA-B75M
Corsair CXV2 430 Watts
Corsair Vengeance 4GB 1600MHz Ram
Hitachi 500GB 7200RPM 3.0 GBPS HDD
Cooler Master Elite 350 cabinet
Samsung 20inch LED monitor with 1600x900 max resolution
LG DVD writer

I wont be adding any other components other than another corsair vengeance ram which i will add in 3-4 months time. Also the 7870 requires 2x6 pin power connectors but my PSU has only one 6 pin power connector but some people are suggesting that a 7870 can be used with my PSU.

So can I use a 7870 with my config without any problems or should I go with a GTX 660?
Also will the i3 3220 bottleneck the 7870 at 1600x900?


Thanks in advance for the help
 

Face2Face

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Jun 6, 2001
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Reading this article on the XFX 7870 http://www.legitreviews.com/article/1967/1/
In the article it states "XFX is recommending at least a 500 watt power supply with 32 amps on the 12v rail"

Your PSU has a 32amp 12v rail, so you are good to go. Your PSU has a 6+2 pin connector so it can dish out 150 watts from that connector ( Which is the same as two 6pin connectors) The 7870 will come with a two molex to 6 pin adapter you can use with your PSU. I would go with the 7870.

Not sure about the CPU bottleneck, I imagine it would in some games...
 

Eureka

Diamond Member
Sep 6, 2005
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You'll be fine. I had an i5-3570k + 7970, both OCed that drew less than 400W. You'll need an adapter to convert a 4-pin molex to a 6-pin PCIe, but your PSU can handle it.
 

lehtv

Elite Member
Dec 8, 2010
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It would work without problems, yes - you'd need to use the 4-pin molex to 6-pin PCIe power adapter. 7870 consumes less than 150 watts at full load and your other components are very low power. Most of the time when gaming you won't be using more than about half of the PSU's rated wattage.

However I don't think the 7870 is a great match for the i3 on that resolution. Even on 1080p, I probably wouldn't go for anything better than a 7850 or GTX 660. For anything faster an i5, preferably overclocked (for games limited to two threads) is a better idea. 1600x900 is only 70% of the pixel count of 1080p which means that CPU bottlenecking raises its head much more easily (you could say 1/0.7 = 1.4 = 40% more easily). If you have plans to upgrade to 1080p sometime soon, I'd recommend 7850 2GB or GTX 660 2GB, otherwise 7850 1GB at most. Even 650 Ti or 7770 would be fine. It does depend on the game though - what games do you play?

Reading this article on the XFX 7870 http://www.legitreviews.com/article/1967/1/
In the article it states "XFX is recommending at least a 500 watt power supply with 32 amps on the 12v rail"
CX430 V2 has 28A on the +12V. The new CX430 80+ Bronze has 32A.
 
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seadrag0n

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It would work without problems, yes - you'd need to use the 4-pin molex to 6-pin PCIe power adapter. 7870 consumes less than 150 watts at full load and your other components are very low power. Most of the time when gaming you won't be using more than about half of the PSU's rated wattage.

However I don't think the 7870 is a great match for the i3 on that resolution. Even on 1080p, I probably wouldn't go for anything better than a 7850 or GTX 660. 1600x900 is only 70% of the pixel count of 1080p which means that CPU bottlenecking raises its head much more easily. If you have plans to upgrade to 1080p sometime soon, I'd recommend 7850 2GB or GTX 660 2GB, otherwise 7850 1GB at most. Even 650 Ti or 7770 would be fine. It does depend on the game though - what games do you play?
I want to play Crysis 3 @ High if possible or @ Medium with 30+ fps as this seems to be a very demanding game

also on the PSU box it says it is 80 PLUS certified
 

Termie

Diamond Member
Aug 17, 2005
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You're fine in all respects. The 7870 plus 3220 won't use much more than 200w total.

And as for bottlenecks, the 7870 and 3220 are a pretty good match. In most games, the 3220 won't come close to bottlenecking the 7870. In some games, it will be a bit closer, but not enough of a problem to step down to a lower-end GPU.

For instance, Far Cry 3 is relatively taxing on CPUs. Compare these two benchmarks:

GPU: http://www.techspot.com/review/615-far-cry-3-performance/page3.html
CPU: http://www.techspot.com/review/615-far-cry-3-performance/page6.html

The 3220 and 7870 top out at almost exactly the same level - between 53 and 55fps. In most games, it wouldn't be nearly so close.

As for Crysis 3, nobody knows what the requirements will be, but my guess is that it would take an entirely different system for you to play it at high.
 

lehtv

Elite Member
Dec 8, 2010
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Termie said:
And as for bottlenecks, the 7870 and 3220 are a pretty good match. In most games, the 3220 won't come close to bottlenecking the 7870. In some games, it will be a bit closer, but not enough of a problem to step down to a lower-end GPU.
You could say that for 1080p, but on 1600x900 it'd be comparable to saying i3-3220 is a good match for an overclocked 7950 for 1080p... not even close

seadrag0n said:
I want to play Crysis 3 @ High if possible or @ Medium with 30+ fps as this seems to be a very demanding game
My guess is that Crysis 3 will be quite GPU dependent but I would not count out the risk of bottlenecking on your resolution. High settings at 30 fps should probably be doable, and I'd expect the jump to Ultra be very demanding and also the drop to Medium to reward you with a lot more frames. I would say that Crysis 3 is probably going to look good enough at lower settings settings that a higher framerate will make for a much better gaming experience. 30 fps is like a slide show to me, 50-60 fps is pretty much a requirement.
 
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seadrag0n

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You're fine in all respects. The 7870 plus 3220 won't use much more than 200w total.

And as for bottlenecks, the 7870 and 3220 are a pretty good match. In most games, the 3220 won't come close to bottlenecking the 7870. In some games, it will be a bit closer, but not enough of a problem to step down to a lower-end GPU.

For instance, Far Cry 3 is relatively taxing on CPUs. Compare these two benchmarks:

GPU: http://www.techspot.com/review/615-far-cry-3-performance/page3.html
CPU: http://www.techspot.com/review/615-far-cry-3-performance/page6.html

The 3220 and 7870 top out at almost exactly the same level - between 53 and 55fps. In most games, it wouldn't be nearly so close.

As for Crysis 3, nobody knows what the requirements will be, but my guess is that it would take an entirely different system for you to play it at high.
i have seen plenty of videos on youtube of Crysis 3 alpha gameplay and from the looks of it an i3 2120 and a HD 6850 are able to run crysis on 30+fps on high at 1680x1050
 

Termie

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You could say that for 1080p, but on 1600x900 it'd be comparable to saying i3-3220 is a good match for an overclocked 7950 for 1080p... not even close
While I understand your argument in theory, it's really quite theoretical.

Let's take some numbers from TechSpot:

At 1680x1050, a 7870 can hit 62fps in Far Cry 3, which is indeed higher than what the 55fps a 3220 can support: http://www.techspot.com/review/615-far-cry-3-performance/page2.html

However, you could simply increase the load on the GPU using 4xAA, and it is quickly brought to its knees in Far Cry 3, even at 1680x1050, making the GPU the obvious bottleneck: http://www.techspot.com/review/615-far-cry-3-performance/page5.html

Far Cry 3 is really at the extreme for CPU loads. A more typical game might be Hitman Absolution:

The GPU can hit 49fps at 1680x1050: http://www.techspot.com/review/608-hitman-absolution-performance-benchmarks/page2.html
The CPU can sustain 46fps: http://www.techspot.com/review/608-hitman-absolution-performance-benchmarks/page6.html

Just apply 4xAA and the GPU is slammed, dropping to 36fps: http://www.techspot.com/review/608-hitman-absolution-performance-benchmarks/page5.html

So, overall, I'd still say that for 1680x1050 (or even 1600x900), if you're using maximum quality settings in brand-new games, the HD7870 will still be the bottleneck on a 3220. It's close, but so close that the 7870 is a bad investment.

I'm not all that interested in discussing Crysis 3 gameplay, as the final build is not even close to upon us - if the OP isn't playing any games right now, he might as well wait until Crysis 3 actually comes out, otherwise, he should base his decision on what games he's currently playing, since we know what those games require in terms of CPU and GPU.
 
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seadrag0n

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While I understand your argument in theory, it's really quite theoretical.

Let's take some numbers from TechSpot:

At 1680x1050, a 7870 can hit 62fps in Far Cry 3, which is indeed higher than what the 55fps a 3220 can support: http://www.techspot.com/review/615-far-cry-3-performance/page2.html

However, you could simply increase the load on the GPU using 4xAA, and it is quickly brought to its knees in Far Cry 3, even at 1680x1050, making the GPU the obvious bottleneck: http://www.techspot.com/review/615-far-cry-3-performance/page5.html

Far Cry 3 is really at the extreme for CPU loads. A more typical game might be Hitman Absolution:

The GPU can hit 49fps at 1680x1050: http://www.techspot.com/review/608-hitman-absolution-performance-benchmarks/page2.html
The CPU can sustain 46fps: http://www.techspot.com/review/608-hitman-absolution-performance-benchmarks/page6.html

Just apply 4xAA and the GPU is slammed, dropping to 36fps: http://www.techspot.com/review/608-hitman-absolution-performance-benchmarks/page5.html

So, overall, I'd still say that for 1680x1050 (or even 1600x900), if you're using maximum quality settings in brand-new games, the HD7870 will still be the bottleneck on a 3220. It's close, but so close that the 7870 is a bad investment.
u mean that a GTX 660 or HD7850 with i3 3220 will perform better than a HD 7870 with i3 3220?
 

seadrag0n

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Dec 8, 2012
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No, that's not quite it. But at certain settings, for instance at 1600x900 without AA, all three may perform identically. In no situation would the 7870 be slower.
thanks for replying to my questions

so should i get a GTX 660 or a HD 7870(cause in my country 7870 is only little bit costlier than a gtx 660) or should i wait for Crysis 3 to launch and see how it performs?
 

Eureka

Diamond Member
Sep 6, 2005
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u mean that a GTX 660 or HD7850 with i3 3220 will perform better than a HD 7870 with i3 3220?
Basically, he's saying that the extra frames that you would get with the 7870 won't happen because the i3 can't support that many frames.

Which isn't necessarily true, if you have huge GPU demand and little CPU demand. If say, you were playing a graphically intensive game which didn't have much in the way of physics, you'd still see an improvement by going with a 7870 over a 7850.

If it's a little bit costlier, I'd say the 7870 because it's a bit faster than a 660, and I think with a graphically intensive game, it could come into use.
 

Termie

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Aug 17, 2005
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thanks for replying to my questions

so should i get a GTX 660 or a HD 7870(cause in my country 7870 is only little bit costlier than a gtx 660) or should i wait for Crysis 3 to launch and see how it performs?
The 7870 is about 5-10% faster than a 660, so I wouldn't pay more than 10% extra for it, given the specs of the rest of your system.

And of course, if you're not going to play any games before Crysis 3 comes out, there's no reason to buy anything right now, as the prices will probably drop in the next few months.
 

lehtv

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Dec 8, 2010
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While I understand your argument in theory, it's really quite theoretical.

Let's take some numbers from TechSpot:
First off, average framerates never show the magnitude of framerate dips during CPU heavy moments, be it in a CPU heavy game or not. What a fast CPU is primarily bad good for is framerate stability, not better averages. Conversely, a faster GPU may provide better averages but during CPU heavy moments it will be just as bad as a lower performing card, thus making framerates less stable.

At 1680x1050, a 7870 can hit 62fps in Far Cry 3, which is indeed higher than what the 55fps a 3220 can support: http://www.techspot.com/review/615-far-cry-3-performance/page2.html

However, you could simply increase the load on the GPU using 4xAA, and it is quickly brought to its knees in Far Cry 3, even at 1680x1050, making the GPU the obvious bottleneck: http://www.techspot.com/review/615-far-cry-3-performance/page5.html

Far Cry 3 is really at the extreme for CPU loads.
1. 1680x1050 is 20% more to render than 1600x900. On the lower resolution, CPU bottlenecking will be more severe. This also partly invalidates the Hitman Absolution results.
2. The numbers in reviews are with stock clocked graphics cards. You could quite easily get 7870-level performance with an overclocked 7850, whereas overclocking the 7870 less likely to provide substantial benefit because of bottlenecking.
3. That you see a bottleneck CPU-heavy games like FC3 is a good reason to go for the lower performing card and use the money saved for a future monitor upgrade instead.

I'm not convinced the inbuilt benchmark in Hitman accurately depicts CPU load in actual gameplay
 
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Termie

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I agree with your comments on the effect of CPUs on minimum framerates, but I challenge you to find any data on that outside of my threads in this forum, for example this one: http://forums.anandtech.com/showthread.php?t=2274887

;)

While I wasn't focused on duals versus quads, what I found in my limited testing using two cores is that a fast dual-core CPU with hyperthreading (like the 3220) is just as good as a lower-clocked quad without hyperthreading. Based on TechSpot tests, I'd guess that the 3220 is every bit the equal of a Phenom II X4@3.5, with regard to both averages and minimums.

Putting that aside for a moment, let's look at cost. Right now on Newegg, a 7870 costs $35 more than a 7850, or put another way, 20% more (for 20% higher performance). Assuming the price difference is the same where the OP is shopping, the 7870 makes sense, even if it's CPU-bottlenecked in some games at 1600x900. In many games, including Crysis 3, it most likely will not be. I gave him a worst case scenario with Far Cry 3, which suggested that it was a close call. In most situations, it will not be.

If the OP finds that the price difference is much greater than 20% between the 7850 and 7870, then yes, he should start thinking about buying a 7850 instead, and perhaps save some money for other upgrades. But saving a few dollars buying a 660 instead of 7870, for instance, because he might be CPU-bottlenecked in a few games, is just silly, in my opinion.
 
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willomz

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A 660 and 7870 are very close in performance on most games. At 1600x900 I would imagine very little difference at all. The 7870 is only really noticeably better @ 2560x1600.

It would all depend on price and model for me, do you have links to the different cards you are considering?
 

seadrag0n

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Dec 8, 2012
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A 660 and 7870 are very close in performance on most games. At 1600x900 I would imagine very little difference at all. The 7870 is only really noticeably better @ 2560x1600.

It would all depend on price and model for me, do you have links to the different cards you are considering?
i live in india so i have to buy locally only and i am going for the cheapest variant of the cards available here

Gigabyte GTX 660 for 15000 INR (276 USD)
Gigabyte GTX 660 for 16000 INR (295 USD)
Sapphire 7870 non-flex edition for 16500 (303 USD)

My budget is 16500 INR(303 USD), so which one should i go for ?
 

Termie

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i live in india so i have to buy locally only and i am going for the cheapest variant of the cards available here

Gigabyte GTX 660 for 15000 INR (276 USD)
Gigabyte GTX 660 for 16000 INR (295 USD)
Sapphire 7870 non-flex edition for 16500 (303 USD)

My budget is 16500 INR(303 USD), so which one should i go for ?
Did you mean the HD7850 is 15000 INR? You listed the 660 twice.

Based on those prices, I would get the 7870.
 

seadrag0n

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Did you mean the HD7850 is 15000 INR? You listed the 660 twice.

Based on those prices, I would get the 7870.
sorry about that...

Gigabyte GTX 660 for 15000 INR (276 USD)
Zotac GTX 660 for 16000 INR (295 USD)
Gigabyte 7850 for 13500 INR(248 USD)
Sapphire 7870 non-flex edition for 16500 (303 USD)

should i consider the 7850?
 

Termie

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sorry about that...

Gigabyte GTX 660 for 15000 INR (276 USD)
Zotac GTX 660 for 16000 INR (295 USD)
Gigabyte 7850 for 13500 INR(248 USD)
Sapphire 7870 non-flex edition for 16500 (303 USD)

should i consider the 7850?
Oh, that changes things quite a bit. I would probably get the Gigabyte 660, as it's half way in between the 7850 and 7870 in price, but much closer to the 7870 in performance.
 

lehtv

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I would get the 7850 2GB and save the rest for a monitor upgrade down the road.
 

lehtv

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Then the 660 is good, especially if you don't overclock (7850 overclocks better).
 
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