GT640M 1GB vs 2GB

Could anyone tell me what the gain would be from a 2 over a 1 GB GT640M?

I'm wondering because both the Sony Vaio S13 and S13a use the 640M except the 13A has the 2GB version but has 4 hours battery life instead of 8 hours. I'm wondering if the better graphic card is worth the change since all other parts can be configured as equal.

Thanks

 

Not much gain.

It looks like the 640M is using DDR3 for video ram which is slower than what modern desktop cards use nowadays, so basically, you wouldn't be able to use anywhere near 2gb of video ram effectively since the memory speed is slow.

 

As above, 1GB will be more than enough

 

This isn't entirely true guys. He could be playing older games that are not too demanding but with massive texture mods. You never know really. If it's not an expensive upgrade, an extra GB of vRAM could only help...

But all the same, if you're not doing anything with massive textures that remains relatively lax in other departments, the increase in vRAM won't be too noticeable, if at all.

 

Even still, the memory size won't make a significant difference because the bottleneck will be the bandwidth to push those textures.

Sent from my Galaxy Nexus using Tapatalk

 

Thank you for the information guys!

 

Both versions of the 640M are fast - twice as fast as the 540M it replaces but with even lower power consumption!

 

Still, say you are a massive-texture enthusiast (and still go with a mid-range GPU laptop; weird combination indeed), this is a 13.3" screen we're talking about, albeit 1600x900 pixels. Would you ever be able to tell the texture difference?

IMHO there's no reason to get 2GB vRAM for this machine, gaming-wise.

 

anything below 1200p resolution I don't think you need more than 1GB vram, unless u use multiple monitors.

 

My GT 630(540)M uses a little over 1000MB (1014MB precise) of the total 2GB on 3DMark Vantage.

So I don't see the point why not to get a 2GB 640M. The drawbacks though, if you like to overclock. The max mem clock you'll get is lower compared to 1GB models, most likely due to higher latency and more memory requiring more voltage.

Btw, what's the difference between a 640M and 640M LE, I've heard rumors of the LE being a Fermi rebrand variation on some laptops...

 

VRAM is a cache. Fetching textures from bandwidth bottlenecked VRAM will still be faster than getting them from system RAM or the HDD.

Bandwidth has no bearing on how much the VRAM can be filled up, just how fast it can be filled up.

I was playing BF3 with a 650m 2gb gddr3 at 1280x1024 and it was using up slightly more than 1gb of vram, so there are some games that will want the extra vram. For the vast majority of games it won't matter though.

 

1014MB used in a benchmark program designed to push everything. (and test even when its getting 4fps)

Note that 1GB = 1024MB... so you weren't even using a full GB even under the worst of conditions.

The point is, anything over 1GB has never been proven to be worth much for low to mid-range GPUs as the card will bottleneck in other ways long before the RAM buffer becomes a problem.

I am sure we could make up an impractical situation where the RAM might help slightly... but it really isn't worth a large investment.

If it doesn't cost you anything, and the RAM speeds are the same, then sure, why not. If its a few dollars... /shrug... if its more than $20, don't bother.

For the most part more than 1GB on low to mid-range GPUs is marketing fluff. Don't fall for it.

 

Yeah, you're probably right. But with the 640M having 2x performance compared to a 630M (540M), who knows :O

 

The 640m's fill-rate and memory bandwidth stats are 1.5x to 2x better than the 540m.

Those two stats have a LOT more to do with the performance difference than the amount of RAM. ;-)

 

I'd sayfor the 640m it doesn't matter that much, but as you start going up the food chain, especially with GDDR5 then yeah more memory is desirable. Keep in mind though, that even with my 1.25GB desktop GTX570 i rarely run into buffer size issues. Skyrim with mods at Ultra 1080p comes to mind as an example of where extra memory can be useful, but you need the GPU to be able to push that first.

I see no reason to go for it, but no reason not to go for it either from a technical perspective. I'd say go with the price, 10-20$ difference, get the 2GB, you never know, but manufacturers will likely charge more to make more profit.