New AMD cpu?

[Jimmy2k9]

Ok, so I'm looking to upgrade my CPU from my current AMD Athlon II x4 645. The idea here is to be able to run two HD 6850's in crossfire, as I'm not sure this cpu would be up to the task. Hoping a CPU upgrade along with another 6850 to pair up with the one I have, would be enough to run BF3 on high/ultra at 1920x1080. Other games I play like WoW and Diablo 3 run fine at max settings with my current setup, but BF3, not so much.

I was going to go the Intel route as I know they currently make the ideal gaming cpu's, but I had my previous motherboard die on me and didn't have the cash to buy a whole new Mobo + cpu at that time, nor could I go that long without a computer. So I ended up buying a new am3+ board (Asus M5A97) just last week on sale for $89.

So with me being pretty much stuck choosing from a AMD cpu at the moment, what would be my best choice as a gaming CPU, one that would not bottleneck the two 6850's?


System specs

AMD Athlon II x4 645
Antec Earthwatts 500w psu (will be upgrading this before a second gpu)
Asus M5A97 AM3+ 970 ATX AMD Motherboard
Sapphire HD 6850 1gb
1tb Seagate hdd
8gb Gskill Ripjaws
Cooler Master 430 Elite case

[eidairaman1]

980 if your not into overclocking

[suraswami]

The second PCI-E slot will run at 4x mode only, so not sure if its going to bottleneck the added 6850.

If CF works then the 645 should be plenty.

If CF is not going to work out then may be sell the 6850 and buy a single 7870 or something like that (again its not cheaper route tho).

[eidairaman1]

Originally Posted by suraswami

The second PCI-E slot will run at 4x mode only, so not sure if its going to bottleneck the added 6850.

If CF works then the 645 should be plenty.

If CF is not going to work out then may be sell the 6850 and buy a single 7870 or something like that (again its not cheaper route tho).

a 4x slot will actually because of the physical wires connected to the slot. it needs to be 8x or faster

[Jimmy2k9]

Originally Posted by eidairaman1

980 if your not into overclocking

I do plan on light overclocking, nothing crazy though.

[Dent1]

Originally Posted by Jimmy2k9

Ok, so I'm looking to upgrade my CPU from my current AMD Athlon II x4 645. The idea here is to be able to run two HD 6850's in crossfire, as I'm not sure this cpu would be up to the task. Hoping a CPU upgrade along with another 6850 to pair up with the one I have, would be enough to run BF3 on high/ultra at 1920x1080. Other games I play like WoW and Diablo 3 run fine at max settings with my current setup, but BF3, not so much.

I was going to go the Intel route as I know they currently make the ideal gaming cpu's, but I had my previous motherboard die on me and didn't have the cash to buy a whole new Mobo + cpu at that time, nor could I go that long without a computer. So I ended up buying a new am3+ board (Asus M5A97) just last week on sale for $89.

So with me being pretty much stuck choosing from a AMD cpu at the moment, what would be my best choice as a gaming CPU, one that would not bottleneck the two 6850's?


System specs

AMD Athlon II x4 645
Antec Earthwatts 500w psu (will be upgrading this before a second gpu)
Asus M5A97 AM3+ 970 ATX AMD Motherboard
Sapphire HD 6850 1gb
1tb Seagate hdd
8gb Gskill Ripjaws
Cooler Master 430 Elite case

Bulldozer X6/X8 and pull off an easy 4.5GHz OC.

[NC37]

Crossfire with a 4x speed isn't worth it. You'd be better off selling the 6850 then investing the extra into a higher end GPU. You wouldn't need to upgrade the PSU then.

For CPU, yeah high end Phenom. Once you hit 3.6/3.7Ghz with the Phenoms the system really feels snappy.

But, have you tried clocking that 645? Those Athlons were not bad clockers. If your HSF is decent, could probably gain enough performance to hold you over until you could afford Intel or Piledriver...or whatever else comes up.

[Dent1]

I run CF 5850s on my Athlon II X4 625 without a problem. but I only game @ 1440x900.

The difference between an Athlon II X4 and Phenom II X4 clock for clock is very similiar. I doubt the switch would justify the cost.

The Phenom II X6 is worth considering, but considering the Bulldozer X6 performs similarly in singethreaded apps, better in multithreaded apps, and overclocks further for the same price. Bulldozer X6 seems like a better choice.

Personally I'd overclock your current Athlon II X4 645, should hit 4GHz easy. Then I'd wait until Piledriver.

[xenocide]

Originally Posted by Dent1

The Phenom II X6 is worth considering, but considering the Bulldozer X6 performs similarly in singethreaded apps, better in multithreaded apps, and overclocks further for the same price. Bulldozer X6 seems like a better choice.

Tom's Hardware found that 2 HD6950's were bottlenecked by an FX-6100, granted the 6850's are lower end, it may not be the best solution. Plus games that are CPU-dependant do horribly on BD Setups due to their lower Per-Core Performance.

[Norton]

Here's some info on 6850's in Crossfire and PCIE scaling

http://www.techpowerup.com/reviews/A...Scaling/1.html

http://www.techpowerup.com/reviews/A...ossFire/1.html

It looks like you may lose around 5-10% of the full Crossfire benefit due to one slot being at X4 but you may be able to overcome that by overclocking your GPU's a bit.

Still not a bad performance boost over a single 6850...

[Jimmy2k9]

Thanks for the help everyone, very much appreciated.


I think what I will do for now is invest in a CPU cooler (currently using stock HSF) and see what I can gain off this 645 with some OC'ing. I guess I should be trying to avoid sinking anymore money into an AMD build when Intel is clearly making the superior cpu's atm. I'm just a "right now" kinda guy and was looking for quick solution, hopefully I can OC this thing and see a difference.

[eidairaman1]

Originally Posted by Jimmy2k9

I do plan on light overclocking, nothing crazy though.

Well in that case a 980 would be the fastest Quad Core You can get that isnt overclocked but leaves room for overclocking, but Most would Recommend the 955, 960T, 970, 975 before the 980.

If you dont want to overclock heavily a 970 would work. Now I believe the 970,975 are Thuban Core Parts like the 960T

if you can find a 1090T or 1100T go for it.

Otherwise in order to get performance levels of the Phenom II stock or overclocked in the Bulldozer FX youd have to heavily overclock them as their Single to Quad Threading is lacking

Originally Posted by xenocide

Tom's Hardware found that 2 HD6950's were bottlenecked by an FX-6100, granted the 6850's are lower end, it may not be the best solution. Plus games that are CPU-dependant do horribly on BD Setups due to their lower Per-Core Performance.

So Im assuming youd pick the Phenom II then over the FX.

Because In reality there is always a bottleneck no matter where you go because of physical limitations of all computer parts.

You can always overclock the Athlon II but you will have to do it via the FSB because the multiplier is locked from going higher.

Id recommend Coolers from Cooler Master or Thermal Right for any CPU out there right now

Originally Posted by NC37

Crossfire with a 4x speed isn't worth it. You'd be better off selling the 6850 then investing the extra into a higher end GPU. You wouldn't need to upgrade the PSU then.

For CPU, yeah high end Phenom. Once you hit 3.6/3.7Ghz with the Phenoms the system really feels snappy.

But, have you tried clocking that 645? Those Athlons were not bad clockers. If your HSF is decent, could probably gain enough performance to hold you over until you could afford Intel or Piledriver...or whatever else comes up.

Hell even at factory speed they are snappy. My Bro has a 555 BE unlocked to a 955 BE and its quick with a 6770 (Yes its a Middle Ground machine with 64bit windows, built by myself n maintained

[JrRacinFan]

Originally Posted by Dent1

Bulldozer X6/X8 and pull off an easy 4.5GHz OC.

Originally Posted by eidairaman1

Most would Recommend the 955, 960T, 970, 975 before the 980.

if you can find a 1090T or 1100T go for it.

And I agree with both of you to an extent. But, look at an overclock to reduce some scaling bottleneck, specifically NB frequency. Most of the 960T lineup when paired with a midrange air cooler will do 3.6Ghz/3.8-4 Turbo w/2.6-2.8Ghz NB.

[eidairaman1]

Originally Posted by JrRacinFan

And I agree with both of you to an extent. But, look at an overclock to reduce some scaling bottleneck, specifically NB frequency. Most of the 960T lineup when paired with a midrange air cooler will do 3.6Ghz/3.8-4 Turbo w/2.6-2.8Ghz NB.

Ya and I recall Phenom II having Higher IPC over Bulldozer stock for stock so it doesnt need the clock speeds that FX needs

Honestly Bulldozer is like Prescott- Clock extremely high but they get hot.

[Dent1]

Originally Posted by eidairaman1

Ya and I recall Phenom II having Higher IPC over Bulldozer stock for stock so it doesnt need the clock speeds that FX needs

Honestly Bulldozer is like Prescott- Clock extremely high but they get hot.

But we are talking about +5% / -5% swing, it is pretty negligible difference. Typical Phenom II OC is about 3.8GHz area, Bulldozer a typical OC is 4.5GHz area. Even in single threaded Bulldozer would be miles faster with a 600-700MHZ OC handicap.

Originally Posted by xenocide

Tom's Hardware found that 2 HD6950's were bottlenecked by an FX-6100, granted the 6850's are lower end, it may not be the best solution. Plus games that are CPU-dependant do horribly on BD Setups due to their lower Per-Core Performance.

But what choice does the OP have? He only has two paths, Phenom II or Bulldozer. Both will to some degree will bottleneck performance. Single threaded performance and price are identical, the only thing that separates the two is maximum OC and this is where Bulldozer can be justified.