Can a cpu bottleneck a crossfire config if it wasnt bottle necking it while in single config

[NINJA_5]

I have a fx 4300 quad core cpu and a r9 380 (not top of the line but still runs all games no problem from what ive seen) it has no bottlenecking problems from what i can tell and works amazing all around. But i am adding a second r9 380 to my machine and was thinking will it start to bottle neck since theres pretty much double the power or will it not since it acts pretty much as a backup.

Thanks in advance for the help i really wanna know before i do.

 

[dontlistentome]

It's tricky, because Crossfire doesn't work the same way in all games. Plus you won't always get double the power just because you have double the videocards.

I'd use MSI Afterburner to see your CPU usage and GPU usage while you play. If you're at 50-60% CPU use, but GPU use is up around 100% during the action, I think you can take that as a good sign you'll get more performance from Crossfire. Of course this assumes your game or games will use Crossfire well, that your motherboard is Crossfire enabled, and that your power supply is good enough to support both cards.

 

[Aspiring techie]

It will definitely bottleneck two R9 380s. My guess is that adding the second 380 will only help out some in games.

 

[NINJA_5]

I know its not ganna double the power. Itll just be like a support kinda. And how do you know its ganna bottleneck have you tested just wanna know to see if i need to get a better cpu soon

 

[bishopi5]

Avoid crossfire... you will only be able to use the second card in benchmarks and "amd" titles. Most of the time you will get less performance then 1 card.. and as mentioned above, if you are playing a game that CAN utilize AMD crossfire (not many) your CPU will definitely bottleneck

 

[maxalge]

I know its not ganna double the power. Itll just be like a support kinda. And how do you know its ganna bottleneck have you tested just wanna know to see if i need to get a better cpu soon

the 4300 is a bottom tier cpu, a 380 is about max it can handle


that platform is dead, dont waste further money on it


if you want more gpu power it's time for a complete system upgrade

 

[NINJA_5]

Well im going to get my second one from a guy for 35 dollars so im definetly going to get it anyway since i payed 200 for the one i have now and i just wanted to know when i should uograde my cpu or if i needed to at all so thank you i will definetly be upgrading soon

 

[Karadjgne]

That's also assuming the psu can handle the CF. You'll want 750w from a decent psu. If you don't have that, you'll be spending more for a psu replacement, so your $35 card will cost you @$100 or more.
Many Dx11 titles only show limited support for CF, you will be lucky to get 40% out of the second card unless you run an AMD optimized game, then you might get 70ish% our of it, not close to double the power. More games show less than 40% and there's more than a few that are so abysmally optimized they show negative %, meaning you'd get better playability from just a single card.

Then there's your mobo, it may not support the cpu upgrade to any of the stronger fx Cpus, landing you with a CF that's next to useless, and $100+ missing from your wallet.

 

[NINJA_5]

Yes i do have a 750 psu and im nkt expecting god like improvement just to keep things stable like i said games run great as is so im fine if its just a ornament until i uograde my psu for that price. And yes i can upgrade my cpu since my mobo supports am3+ thats how im able to use a fx cpu

 

[Karadjgne]

The 760g chipsets are AM3+ as are the 970 chipsets and 990Fx chipsets. But that does not mean any FX will work. Mostly, no 760g chipsets will support a 125w FX cpu, they'll only support the 95w FX, (most 4 series, a few 6series). The 970 is iffy, most will support upto the 8 series 125w FX, some won't, some will support the 9 series 220w cpus. The 990Fx will support any 4/6/8 series FX, but again, there's a list of maybe 6-8 actual boards that'll support the 9 series cpus. AM3+ means not much, just that the cpu will physically fit, the chipset and mobo itself will determine exactly what cpu it will support, and any level of possible OC. (OC really helps any of the FX cpus)

 

[dontlistentome]

Ninja_5, I can't speak for anyone else but I'm just trying to help you by advising you not to spend money on things that won't accomplish anything. It sounds to me like you want crossfire just to say you have crossfire. That's fine if you have extra money to throw away. I don't like to spend money on computer parts unless I'm getting performance from them.

My recommendation would be to use this FX 43xx/380 system as is until you are ready to build a new system, don't upgrade this one. In my opinion it's too late for upgrades on this system, it's so outdated that you are better off applying that money to new technology.

 

[NINJA_5]

Yes i do agree and thank you i just recently build it as my first ever pc and im slowly upgrading on what needs to be done depending on the kind of work i do on it and what needs to be sped up graphical power isnt a problem but i saw someone was practically giving away a brand new r9 380 card and thought it wouldnt hurt to future proof since i still am definetly getting a cpu ill see a performance boost when it happens. But i do agree but if i do it later a deal like this would just be gone.

 

[Karadjgne]

That makes more sense, get the gpu and shelve it. DX12 titles don't use CF as such, they use the 2x gpus together, so building an updated pc and keeping the 2x 380s would definitely add plenty of gpu power. For $35 that route would be a steal. Cost @ $350 for a 1070 to get equitable power under DX12.