Will my 920XM bottleneck two 6970Ms too badly?

I ask this because I'm buying another 6970M off a user here for CrossfireX, but I'm not entirely sure how much of a gain I'd get even if both were at stock clocks. (They'd have to be undervolted too to be within the limitations of the Adapter.)

I saw on NotebookCheck.net that the 6970Ms in CrossfireX managed to score around 18k in Vantage at stock, with a 940XM, for the overall P score. However, the other machines listed managed to score over 20k and the other machines used either a 2nd gen i7 or the i7-990X used on the Clevo X7200.

I'm just a little worried I'll suffer from bottlenecking these GPUs too badly.

Here's what I scored in Vantage with the one 6970M @ 825/900 and the 920XM turbo @ 2.53GHz: AMD Radeon HD 6970M / 6990M video card benchmark result - Intel Core i7-950 Processor,Alienware score: P14149 3DMarks

 

920XM isn't that powerful now. A good SB can smoke it and certainly Ivey Bridge. But for gaming, I think the 920XM will be enough for your 6970M. 6970M likely still the bottleneck in the games.

Sounds to me though, if you sell your current 6970M and buy a 7970M you'll get a lot more performance. The XF scaling isn't always great on games, it depends on the games and plus the drivers issues and problems that come with mulit-gpu systems just not worth it.

I always say, powerful single card > Multi-GPU setup. Always.

 

It wont bottleneck badly, neither to the matter when you'll notice it, but it'll lower your score in benchmarks and the FPS slightly, but nothing to worry about (unless I'm all retarded and wrong, which I'm sure I ain't)

 

Bro, is your 920xm overclocked? Just bump it up a little and you'll be fine. Overclocked 920xm to mid 3's is still a good CPU. It wont bottle neck you

 

Well that's just it. I have it overlocked to 3.2GHz at the moment but when I get the second 6970M, that overclock is going away and the CPU will be at stock.

Both GPUs will be undervolted to lower the power draw on the PSU as well.


I'll be working with this setup essentially:

- i7-920XM @ Stock (Stock turbo speed for all four cores is only 2.26GHz)
- Twin 2GB 6970Ms in CrossfireX @ Stock (Undervolted to reduce power draw)
- Dell Alienware 210/240w PSU

 

The 920XM is still a fairly fast processor. It scores the same as an Ivy Bridge Core i5 3320M, at 4463.

Sent from my SGH-T769 using Tapatalk 2

 

I still think that you will be fine. The cpu won't be a bottleneck

 

To be honest, only shoddy ports of games (GTA IV, I'm looking at you) will rely on the CPU, for practically everything else, your GPU is what matters. So no, it will not be a bottleneck.

 

If you push your 920XM upto 3.2ghz over 4 cores you can achieve 5k+ on 3DMark as i did and that is on par with the benches of an I7 2630QM so you do not need to worry the XM models are monsters if you treat them right.

 

for me i can only get 3.33Ghz for overclocking for gaming and folding its like 3.2GHz which is plenty. The only games will throttle are single threaded games CS:S Rome total war with 25k units and so on and so forth but you will most likely never notice it

 

Huh.. this is a very old thread but I'm surprised at the low bench scores that you guys get with 920xm. My top highest CPU score in 3dmark11 Performance is around ~6800 marks. I was considering switching to a M17X r2, keeping the CPU and GPU and adding another 7970m into the mix. Any opinions? (Sig related, my 3dmark11 score on this machine. Unfortunately GPU is a bad overclocker. I use a delta 150W PSU).

 

Yeah I was wondering whats up with the bad scores. My previous 920xm held its own even versus Sandy bridge, which only the 28xxqm clearly beat it up. On stock, it is bested by the 26XXQM cpus, but once OC it holds its own well easily.

My previous laptop at 3Ghz was scoring 6500 on 3dmark11 and almost 18k on vantage which is on par or higher than 26XXCPUs and even nearly 27xxQM cpus. And that was not my max oc. I remember being unable to match or win vs the 28xx CPUs but otherwise I never really had problems gamingwise with it.

At stock speed you might bottleneck in some cpu dependent games, otherwise you should be fine. Performance drop from cpu should not be too pronounced. You should overclock at 2.4ghz at least with the dual GPUs, it shouldn't kill your PSU. I commonly gamed around 2.6ghz because I rarely saw the need for more in my previous setup.

 

i wonder if there is a commercial power supply that you can get that will run at 19volts. i have a 12v 30a powersupply that i use for my 3d printer and the voltage is adjustable up to like 15v and down to 10v. if you could find one you could just get like a 20v psu and undervolt it 19v, then just attach the tip you need and you could overclock to your hearts content.

heres an example 350W 18V 20A Switching Power Supply Radio LED Charger USU | eBay

they go for about 60 is bucks on ebay, and the voltage is adjustable +/- 1.8v running at 18v with up to 20amps, you would just need the proper tip.

 

Wow, that's pretty cool. While I don't have a need for that, it's a great option if i ever move onto dual-gpu configs.