780M vs 750M SLI

How big of a difference really is there between these GPUs ?

I know a 750M SLI performs basically on par with a 770M, and the 770M is 30-40% slower than a 780M ?

But in actual practical usage, we're talking about 10-20 frames. And a laptop featuring a 780M like a Clevo 170SM runs minimum of 1800, whereas I can get a Lenovo Y510P for 1200.

Is the difference in frames worth the extra 500-600 dollars ?

 

I would say it scales 0-80% so GT750 SLI are more like GTX765, ofc if game supports SLI in the first place.

GTX780 murder GT750m SLI any how you turn it, even GTX770m is alot better choice.

 

Really? It seems according to this, the 750m sli even outperforms the 770m in some cases...

Review Lenovo IdeaPad Y510p Notebook - NotebookCheck.net Reviews

 

You got that right, it performs just a gtx770m, in some games its even better, I think Undyingghost might have meant the GT650m sli which indeed is on pair with the gtx765m.
If you dont plan on playing the latests games on ultra settings then I'd go for the gt750m sli, I have the one with the gt650m sli and I can play any game on at least high @ 1080p.
Surely the gtx780m is a beast and more future proof but 500-600 more dollars? not worth it imo.

 

780M = 1536 shaders, 771/1250, 256-bit
770M = 960 shaders, 811/1000, 192-bit
750M SLI = 768 shaders, 941/1250, 128-bit

There's no way the 750Ms are within 30-40% of the 780M. I used Notebookcheck's Ultra benchmark preset to find the 780M's adavantage over the 770M, and only averaging the 15 most recent games at the Ultra preset, the result was 51% in the 780M's favor.

I don't expect the 750M SLI to keep up with the 770M in next-gen ports, not at 1080p.

 

As kevin said, 780m = 50-60% better than 770m.
But if the 500-600 difference is to big I would suggest 770m over the SLI 750m, smaller, lighter, less consuming notebook and you avoid SLI problems like games not supporting it or simply offering poor scaling

 

I agree with the above. Not only are you shader limited, but the 128bit bus is a big limiting factor. Combine that with the hope that SLI is supported, it's not going to be a strong solution for upcoming games when the demanding games out now are struggling. So in short, yes, it's a huge difference. I'd rather save and spend more money to play the games comfortably then spend a lot of money and struggle.

Edit: You have to ask yourself if demanding games of today and the likely fact that games of tomorrow will be similar to the demanding games of today are worth the extra 20ish frames. That's the difference between averaging 19 FPS (Crysis 3) to 30FPS. Basically: playable vs unplayable.

Now if you can comfortable playing games on medium/high and truly only want to spend the amount listed, then by all means, go get it! I personally would just buy a used system as 750m SLI is weaker than a 580m SLI setup (which is still a good setup). Now if a 770m single card is only a few % off 750SLI, I would go for the single card solution. It's always better to get the best single card solution over two cards that offer similar performance. The 750mSLI is more powerful than I was thinking when writing my response but I think that in one year, you may be disappointed you spent all that money unless you are comfortable playing at medium settings.

 

I know what you guys are saying, basically the 750m sli may be good now but suffer and fall behind in the next gen.

But can we really say the 780m will fare so much better? As it stands, some games the 780m is offering very little margin over the 770m. Take bio shock for example, 46 FPS vs 38.

What I really want to say is, in about 2 yrs ill likely repurchase. How likely is it that my clevo is upgrade able. Or can I repurchase another midrange, ie 750m sli equivalent in 2 years.

 

Even if 750SLI matches the 770M in numbers, due to the input lag and increased changes in frame pacing it wont "feel" as smooth. Typically I recommend 20-40% advantage for an SLI setup before it's worth considering over a single card.

 

You are comparing bioshock which is not indicative of the average performance difference between the 780M vs 750m SLI. That game is only 15% off (according to notebookcheck) the 780. However the single card 780m is about 50% more powerful in games/benches etc. Of course some games scale really well or just plain don't run well on any card. If you are buying for two years I would get the 780m as that is about how long that card is viable. A 780m SLI will fare much better for longer. It all depends on what settings you are comfortable with. If you can be comfortable playing at moderate settings for 2 years before you upgrade again (kinda seems weird to spend that kind of money to want to play moderate settings for two years) then by all means....grab the system and enjoy!

Get the best you can afford. Period. then adjust accordingly.

 

Don't forget GPU Boost 2.0. Notebookcheck doesn't list any of the correct Boost clocks but the 750M at stock Boosts to 1058 MHz core under load. The 770M and 780M in turn are also higher than what you listed.

Also, since we're talking SLI, it's actually 768 shaders, 1058/1250, 256-bit @ 160 GB/s.

In any case, OP is talking two very different systems. The biggest advantage of the Clevo besides the obviously stronger GPU is the upgradeability. For many users that alone is worth the price of admission. If you can find a GTX 770M Clevo for not much more than the Y510p that sounds like the best compromise. A single GPU at the same performance level wins any day of the week but the trouble is finding something with a GTX 770M and similar specs for ~$1200.

 

I'd suggest you go for Clevo P370SM and configure it exactly the way you'd want to buy the 177 you want to buy, with 780M, you're better off spending that 500-600 extra now and be able to enjoy all the games at high settings with the 370SM and in a year or so get another 780M and run the Clevo in SLI, instead of upgrading your laptop, upgrade by adding an extra card, its more costly now but its more cost effective considering you can upgrade the CPU and other components too, the Lenovo is NOT upgradeable

 

You can get a Clevo with GTX 770m for under 1200$, P151SM, I would take that any day without an ounce of hesitation over a Y510p, it is even cheaper than the Lenovo if you already have an OS ...

 

You don't get double the memory bandwidth. The data in vram is mirrored between both cards, so it's still the same bandwidth as a single 128bit 750m.

A Sager NP8235 with a 770m can be had for ~$1200 without an OS, while the Lenovo can go for ~$1100 after coupons, and that's with an OS.

 

Effective memory bandwidth is doubled. The frame buffer is mirrored but not doubled.

 

Not to mention that the 770m will likely overclock much higher with less trouble than an SLI system. Heck, I was able to get my 765m to 5500 3DMark 11. SLI, IMHO, is only really good for high end video cards when you can't buy a single card for the same or better performance, and/or the SLI setup is significantly cheaper than a single card at similar performance. The one advantage you'll have with 750m SLI over a single 765m, due to the 128-bit bus is the SLI will perform better at higher resolutions like 1080p because each card will effectively be rendering at half the resolution.

 

Definitely 770m over 750m SLI, if you can it would be better to stick with single GPU.

 

Effective read memory bandwidth is sort of doubled ish, write bandwidth remains the same.

If one card writes something to memory it must transmit that to the other card and have it write it to its memory to ensure they remain in sync so each write operation is doubled plus overhead and is technically more expensive. Luckily data is read more often than written.

Each card has it's own memory to read from but can't draw on the resources of the other card so you will get them reading the same data more than once and also if one cards bandwidth is saturated by a scene then it can't borrow any extra bandwidth from the other.

Crossfire and SLI is not a simple doubling of any resource.

It is 2x384 shaders, 2x128bit GDDR5 and a pool of 1GB or 2GB of memory depending on if each has 1GB or 2GB of GDDR5.

 

I think you're referring to split frame rendering (SFR). Multi-GPU has been using the AFR mode for a long time. Regardless, the memory bandwidth advantage is there with the SLI setup, which is why even 650M SLI outperforms 765M at 1080p with MSAA.

 

On the contrary, with AFR, each card has access to its own memory. Each die renders alternate frames and the bus between a GPU die and its memory is still 128 bit. There isn't a "central" memory that both dies can access. The cards are not memory bandwidth limited with a 192bit bus because overclocking the memory shows very little performance increase, if any. Which means that the 650M SLI outperforming the 765M with inferior hardware is simply nonsense, regardless of what NBC has to say.

 

But if you look at it across every two frames both GPU's are essentially doing half as much work as what a single GPU would. The GTX 765M is still 4 GHz 128-bit GDDR5 @ 64 GB/s just like a single GT 650M. I don't think it's a fluke that 650M SLI outperforms 765M at 1080p Ultra settings in most games tested by Notebookcheck, because the 765M is bandwidth-starved at those settings despite its superior shader and compute power. 650M SLI will be the better performer at 1080p because of that. A 192-bit GTX 765M would be a more balanced combination of compute units and memory bandwidth. They have this on the desktop side and it's called the GTX 650 Ti Boost.

If the Notebookcheck results are "nonsense" please provide your own apples-to-apples comparison of these two GPU's.

If memory bandwidth is so unimportant, how do you explain the GTX 650 Ti Boost being 40% faster than the GTX 650 Ti? 100 MHz more on the core clock won't give you that. It's obvious most of it is due to the large memory bandwidth increase.

 

Generally GT750M SLI more or less equal 770M, but i would still recommend 770M because of Optimus.

@Ben

Clevo's are more expensive where i live. And i'm not too particularily fond of them, i would have easily picked a GT60 over the model you suggested.

 

Where abouts are you from? Potato Island lol ^^

Well to each their own, I prefer the slimmer, dual fan system Clevo, the MSI is to FAT, it looks like a gaming laptop from over half a decade ago .

 

I live on Price Edward Island, Canada. Feel free to google this province, there are more potato fields on it than anything

Depends on what Clevo. I like the W230ST and W740SU, though some others like the P151SM are really un-attractive. Alienware 17 is also a contender in the High-End range, and has the best resale value.

/derail