GTX 690 question

[peterleo]

Hey guys!
I'm thinking about getting a GTX 690. I have done some research and I have the following question:
The card is advertised as having 4 GB of memory. But everyone says that the card only uses 2 GB. In this case why does it have 4 GB if it only uses 2 GB? What is the catch? What am I missing?
I've searched all over and couldn't find the answer...
Cheers!

 

[dipzy]

Its probably because each GPU core has 2GB of Ram and since its a dual GPU card, its advertised as 4GB. I think this is why, 100% sure.

Maybe someone else can make it more clearer

 

[hmmblah]

It'd be the same as if you had two 2GB GTX680's in SLI. There might be 4GB of vram in the system now, but it's only used as 2GB as 2GB is dedicated to each core.

 

[peterleo]

Thanks for the quick reply!
I figured that since it's 2 gtx 680's put together, it has 2 gpu's each with 2 gigs of ram.
I'm trying to figure if the data is shared between the two sets of ram -each one of 2 GB - like in Raid 1...

 

[FTR.4500MHz]

Dipzy is spot on here. Each gpu has 2gigs of dedicated Vram.

If you want to know more search for "Alternate frame rendering" that will explain you how crossfire or sli works.

 

[peterleo]

Dipzy is spot on here. Each gpu has 2gigs of dedicated Vram.

If you want to know more search for "Alternate frame rendering" that will explain you how crossfire or sli works.

Thanks man! Exactly the info I was looking for!

I've looked into it a bit and now it finally makes sense!
So the workload is divided in 2 between the 2 gpu's.
But, if I'm using a three monitor setup, then it is possible that the amount of information of each frame might be a bit much for 2 GB ram, thus reducing performance (like in bf3).
Did I understand the principle correctly?

 

[FTR.4500MHz]

Yes, with 2gigs of vram you will be limited on a 3 screen setup if you plan to play it on "ultra". If your plan is to absolutely get a 690 you must be prepared to turn the settingsdown and also leave some of the eye-candy by side (aa, msaa, af....).
I would rather buy 2 7970/50's since they have 3gigs of vram which in your case will give you a huge advantage over the 690 in a multiple screen setup. And with a decent overclock you'll blow away the 690.

Will prob. be cheaper aswell.

Edit: or you could look at the 4gig versions of the 680.

 

[peterleo]

I've been reading more into AFR, and I've seen that micro-stuttering is a big issue in multi gpu systems - it seems that especially for amd's xfire it's pretty bad.
So I'm wondering how would 2 GTX 690's compare with 2 GTX 680's (4 GB version of 680) when it comes to bf3 running 5760x1200 with everything maxed out? Which would you recommend?
Also, I have a rampage 3 extreme - not sure how pcie v2 on my board might limit the cards compared to pcie v3 on newer motherboards...Or maybe I should just start a new thread for this?
Anyway, thanks for the great info! I appreciate it!

 

[FTR.4500MHz]

Stay away from 4 way sli !!!

 

[peterleo]

That bad? )

 

[FTR.4500MHz]

Bad driver support and in most if not all cases it performs worse then a 680 sli.

 

[Deejeta]

3 screens. Performance will depend on the resolution.
For the price that a 690 is, I would (as stated previously) go for a xfire 79x0 setup. You will then have two cards each with 3gb of memory.
Also there are 4gb 680's around. Pair those up and you would be fine as well.
Hope you have a decent psu either way.

 

[peterleo]

Thanks for all the replies guys! It's really helped me understand some things that were complete misteries for me.
I've owned two 6990's in xfire that gave me nothing but trouble. Think I'll give Nvidia a try this time...
I think I'll go for two 4GB 680's in SLI...but I'm still researching...

 

[FTR.4500MHz]

The best bang for the buck cards are the 7950's atm ! And also the drivers have improved alot.
Last year when i was was running BF3 on my 6950 xfire i didnt notice any problems.

But on the green side it also seems to go pretty well.

 

[BustedHead]

I've been reading more into AFR, and I've seen that micro-stuttering is a big issue in multi gpu systems - it seems that especially for amd's xfire it's pretty bad.
So I'm wondering how would 2 GTX 690's compare with 2 GTX 680's (4 GB version of 680) when it comes to bf3 running 5760x1200 with everything maxed out? Which would you recommend?
Also, I have a rampage 3 extreme - not sure how pcie v2 on my board might limit the cards compared to pcie v3 on newer motherboards...Or maybe I should just start a new thread for this?
Anyway, thanks for the great info! I appreciate it!

Mine is rockin

 

[Rastalovich]

Can someone show linkage to the study that defines having less then 2g in your graphics arsenal is going to muchly impact your tripple screen gaming pleasure at mucho resolution ?

.. and I don't mean a "thread post" that says it's so, or it's someone's opinion/experience. I mean genuine testies.

 

[Josh Weston]

Can someone show linkage to the study that defines having less then 2g in your graphics arsenal is going to muchly impact your tripple screen gaming pleasure at mucho resolution ?

.. and I don't mean a "thread post" that says it's so, or it's someone's opinion/experience. I mean genuine testies.

From a quick looksie on Google, i'm inclined to say that it only ever seems to merit a 1-2fps increase. Interesting...
I would say that the data i've seen is merely talking about FPS, though. From what i've heard, a lack of VRAM can lead to textures not loading properly and all that jazz. Still, that's only from what i've heard people say in aforementioned thread posts...

 

[NRG!]

I cba to make graphs but you don't need 4gbs of vram per card for a 2 way 680/670 sli (skyrim/ heavily texture modded games excluded) @ 5760~x1080. Seems I'll be saying this 'til I'm blue in the face but w/e.

You do generally need 2gbs but it generally depends on the GPU grunt. If the frames are 25fps then you'll lower settings (msaa is a killer for fps and vram @ triple res) which will in turn free up chunks of vram.

If you're close to maxing you can have texture loading issues as above, and if you run out you will drop to 1-3 fps.

edit: I agree with going for 7950/7970 xfire as either spanks 680 SLI.

 

[Recon-UK]

I cba to make graphs but you don't need 4gbs of vram per card for a 2 way 680/670 sli (skyrim/ heavily texture modded games excluded) @ 5760~x1080. Seems I'll be saying this 'til I'm blue in the face but w/e.

You do generally need 2gbs but it generally depends on the GPU grunt. If the frames are 25fps then you'll lower settings (msaa is a killer for fps and vram @ triple res) which will in turn free up chunks of vram.

If you're close to maxing you can have texture loading issues as above, and if you run out you will drop to 1-3 fps.

This is real truth.

A 7870 cannot take use of 2GB of Vram, even in CFX solutions, it is hard to max it all the way out...

My 480's rarely ever run out of Vram at 2560x1600, the only time they did was at 3180x2160 4K res, but that was with absolutely everything cranked in AVP...

 

[NRG!]

tbf though with the 7870s memory bus the options are 1gb, 2gb or 4gb. 1gb is not enough for it.

Unless they were to do nvidia gtx660-style jiggery pokery with the memory.. but 2gb vram will sell more cards than 1.5gb at the end of the day.