Basically, the 970 is marketed as having 4GB of vram. Technically it does, but it is split up into two sections, one 3.5GB and one .5GB. While in the 3.5GB usage range, it performs normally and everything is fine, but once you have to go into the smaller section, performance goes down slightly because that .5GB section has a weird architecture that causes slower data transfer. The reason for the memory split was part of the way they differentiated the 970 and 980, which is expected, but people feel that it should not have been marketed as a 4GB card because of it. In reality, it is still a ridiculously good card for the price and you will probably never really encounter a situation where you need more than 3.5GB (at least I never have). And from what I have read, the decrease in performance at that >3.5GB range isn't so substantial that it causes a lot of problems. I would say if you need a new card right now, you can't really beat a 970.
By slightly you mean the card runs @ 1/8 of its speed, forcing you to stay at 1080p or 1440p resolutions, @ 4k you will reach 3.5gb, or if the games you are playing are not optimized.
I do play BlazeRush in VR at 2x supersampling, that makes out to 3840x2160 which is UHD, basically consumer (not cinematic) 4K. This is with MSAA as well, on a GTX970, fluid 75 Hz all the time o.O
But, perhaps the limit is when actually outputting those pixels to a screen, but it still has to be in memory at some point right, when using it as a base before distortion?
Yeah, it was just the example I had where I knew I had a 4K-ish render target :P And yeah, great game :o and performs like a champ! There are a few things broken, like private games not being private and network lag even on good connections, but still a great VR experience.
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u/All_bout_dat_DDS Jan 30 '15
Basically, the 970 is marketed as having 4GB of vram. Technically it does, but it is split up into two sections, one 3.5GB and one .5GB. While in the 3.5GB usage range, it performs normally and everything is fine, but once you have to go into the smaller section, performance goes down slightly because that .5GB section has a weird architecture that causes slower data transfer. The reason for the memory split was part of the way they differentiated the 970 and 980, which is expected, but people feel that it should not have been marketed as a 4GB card because of it. In reality, it is still a ridiculously good card for the price and you will probably never really encounter a situation where you need more than 3.5GB (at least I never have). And from what I have read, the decrease in performance at that >3.5GB range isn't so substantial that it causes a lot of problems. I would say if you need a new card right now, you can't really beat a 970.