Overclocking 840M in a chassis that can take 650M

Hi all,

Been looking for a slightly better replacement for my Asus N56, which has shorter battery life than I would like. But it seems to be the only machine with all that good things that I want (excellent sound, nice matte screen, fair gaming capability etc). Mine has 650M DDR3 and a 3630M CPU, but there is a version with a 4710HQ and an 840M. Obviously this will last a bit longer on the same battery spec, but might be a bit weaker on gaming due to the 840M. But this is still an N56 chassis, right, so if they're using the same cooling module, there should be a bit of spare heat removal capacity in there too, considering it can cope with a 650M+3630M? That being the case, what are the prospects for overclocking the 840M about 10% so that it more or less equals the 650M?

Cheers in advance.

 

The 840m should perform similarly to the 850m in all respects at 1366x768 or 1280x720. The 650m has the advantage of having GDDR5 though, but with the performance of the GPU not sure if it helps a whole lot. In any case the 840m should OC up the +135MHz limit that Nvidia allows, my 940m does no problem. But of course every chip and laptop is different.

And not sure if laptop will get better battery life unless they included a better battery or optimized the power profile. The GPU with an Optimus system is basically disabled for desktop work and doesn't have a bearing on battery life.

Now if reviews showed the newer laptop gets better battery life then sure, something is different. But if it's just assumption then not necessarily true.

 

Tough call but even if you overclocked a 840m to a 650m it still limited by its 64-bit bus which means lower bandwidth when running games in a higher resolution while your current 650m DDR3 has a 128 bit bus and i can see it strugging of running games in HD resolution but i think maxwell handles memory bandwidth better. I doubt you'll get much of a increase of battery life unless you go with a ULV CPU than a 4710HQ or any quad core.

 

64-bit is fine for 720p or 1366x768. Running a 940m here 1366x768 is about its limit. The FPS doesn't increase significantly when going lower resolution, but drops more significantly when going above it. I'd say 720p is it's "sweet spot". 650m may be able to manage 1080p a bit better because of the 128-bit bus but it's still performance limited and the DDR3 vRAM doesn't help matters much either.

 

Yeah thats true, that explains why the 840m and 940m are still slightly weaker in real time performance and benchmarks than even my 750m which is like a overclocked 650m. I can play some games on 1080p like GRID2, BC2 and some others but yeah DDR3 really limits the performance on higher resolutions than 720p