Video card question

[isagreg]

I remember Dimitris was saying that in order for video card to use 3Gb or more of memory the card's memory interface has to be higher than 256-bit. But the following cards don't meet that requirement:

 

GeForce GTX 770 4Gb 256-bit

Quadro K4000 3Gb 192-bit

Quadro K5000 4Gb 256-bit

 

So what happens there? Can't those cards use all the memory?

Correct me if I misunderstood.

 

Thanks

Edited February 27, 2014 by isagreg

[Dimitris Tolios]

This is for directly paging 100% of the RAM.

 

Not all the resources need to be accessible simultaneously for the RAM to be useful for progressive rendering applications, but for viewport performance, a "2GB" K4000 would not have real deficiencies vs. the 3GB version, much like the 680/770 4GB doesn't have any performance advantage over the 2GB versions.

 

The GK104 (what is used in 680/670/770/760/K5000 etc) has 4*64bit memory controllers.

These controllers can either access 2* GDDR5 memory chips @ 32bit (as it happens in 2GB versions) or 4* GDDR5 chips each in 16bit mode (clam-shell mode). Total memory bandwidth in each case is the same, or 256bit * memory speed (which is the same between 2 and 4GB models).

 

So, in a nutshell, if your goal is better viewport performance, 256bit models with more than 2GB of RAM won't really help.

But for GPU rendering applications that will be pushing more than 2GB, it might be a "make it or break it" situation, and 4GB VRAM might be the only way to go. This is situational ofc...I've seen great GPU renderings using octane back in the days with 512 and 768MB cards, and GPU rendering engines like Vray allow you to compress bitmaps in textures (the main reason you should be blowing your VRam usage) to keep in controlled.

 

nVidia chooses to give these numbers, so that there is a layman-accessible feeling of "upgrade" (why upgrade from a Quadro 4000 to "another-just-2GB-VRAM-GPU?) and also to appear equal or "better" vs. equiv. priced AMD products that use 384bit busses and naturally have 3GB RAM.

Edited February 27, 2014 by dtolios

[isagreg]

Wow, thanks Dimitris for such a comprehensive answer.

 

I'm trying to spec 2 computers for work and home.

At home I have two 30" monitors (2560 x 1600) and at work two 24" (1920x1200)

I went to your website and you recommend having 2 (or more) cards, one for viewport and another for GPU renderings, which makes a lot of sense.

 

Now for GPU renderings the decision is easier (specially after your reply). Looks like Quadros are useless for GPU renderings (except K5000 and K6000, but the prices are brutal). So I think I'll get either GTX 770 4Gb or GTX 780 3Gb.

But for viewport I can't decide what to get: Quadro K2000 (128-bit, 2Gb GDDR5), K4000 (192-bit, 3Gb GDDR5) or just GTX 770/780 to run 2x30" monitors comfortably.

 

The software is usual (ACAD, 3dsmax+VRay, Revit, Rhino, SketchUp and Photoshop), no games.

Don't know if any of those programs will benefit from Quadro, they say 3dsmax 2013/14 works better on GTX lately.

 

Thanks

Edited February 27, 2014 by isagreg

[Lupaz]

 

Don't know if any of those programs will benefit from Quadro, they say 3dsmax 2013/14 works better on GTX lately.

 

I heard the same thing. I have experience with both quadro and geforce.

Although the performance with quadro is better, I had many issues with driver releases for Max with every new 3ds max version. Geforce doesn't seem to require much attention in that respect.

[paneli]

I heard the same thing. I have experience with both quadro and geforce.

Although the performance with quadro is better, I had many issues with driver releases for Max with every new 3ds max version. Geforce doesn't seem to require much attention in that respect.

 

In general I ditched quadros for GTX.

Since Max 2012 the viewports are smooth and work much better for me.

 

But I think my next step would be AMD cards.

Will look up for it when it will be time to upgrade.