I know GTX 660 has a 192-bit memory bus and thus the last 512 MB of its 2 GB memory are accessed at just 64-bit, but does whole memory switch to 64-bit mode when the 1.5 GB threshold is crossed or just the last 512 MB? Please, I've seen much mixed and misleading information on so called "gamer" sites.
I know it's not old HW but please is there anyone who knows?
Here is a good description on how the memory is connected: http://www.anandtech.com/show/6159/the-geforc … 660-ti-review/2
Basically there are three memory controllers, each with 2 32-bit memory channels, and one controller just has more memory attached.
The effective bandwidth depends somewhat on how the actual memory is allocated. It will try to interleave the memory to get an even balance.
Thanks, so it doesn't put the whole card in 64-bit mode when memory usage crosses 1.5 GB? I've read the whole article before but it's not really clear on if the "worst case scenario" applies to the whole card or just the last 512 MB of memory.
wrote:Thanks, so it doesn't put the whole card in 64-bit mode when memory usage crosses 1.5 GB? I've read the whole article before but it's not really clear on if the "worst case scenario" applies to the whole card or just the last 512 MB of memory.
From what I understand, it interleaves the memory between the 3 controllers... Since there is more memory on one of the controllers, you can't always get perfect 192-bit access to the memory.
But this is 'spread out' over all of the memory, so to say.
wrote:I know it's not old HW but please is there anyone who knows?
Didn't expect so see someone say that in this forum 🤣 .
Is there any way to display memory speed in realtime like VRAM usage and temperature in MSI afterburner?
wrote:Is there any way to display memory speed in realtime like VRAM usage and temperature in MSI afterburner?
Yes and no. Yes you can display speed, but it won't achieve what you want. What I mean is: the card dynamically reclocks the GPU and memory in response to load, and GPU-Z (or other applications) can show that. However showing theoretical bandwidth throughput at any given point isn't possible without loading the memory subsystem (which would hurt gaming performance). Due to the interleaving you shouldn't have any significant performance hits under real-world conditions (it's a fast enough card to keep up with modern games), and any application that will demand 2GB+ of VRAM would likely bring the card to its knees regardless of memory bandwidth.
Tom's did a more in-depth test of the 192-bit bus here that you might also be interested in:
http://www.tomshardware.com/reviews/geforce-g … ng,3283-10.html
