Only one gpu active on radeon 3870x2

R

ryane24

Member
I just built my new system with the Visiontek Radeon 3870 X2 and everything is running great! Except for one thing, i dont think both the GPU's are active because it says that i only have 512MB of video memory. I foresaw this problem before i even built the system, so i downloaded the lastest drivers which was suppose to get rid of that problem, but apparently it didnt.
 
my cousin had the same problem. i think he reinstalled both the drivers for each video card untill crystalize center reads both of them. he said he tried like 6-7 times :o

chingchong
 
I've heard one time that you needed to install the drivers twice... Weird... I know...

And you don't add the memory up.
 
Yeah, if those 38's work as if in Crossfire, memory doesn't add up. Both GPU's store the exact same information on their VRAM synchronously, they don't work individually.
 
The memory still doesn't add up, if we're talking 512mb X2. Both cards are working to render the screen right? They both need the meshes, textures, vertices, all the geometrical data loaded into the VRAM.. they both need an exact mirror of the other to get their work done. It's like a RAID 1 array, what's stored in one drive is stored in the other(s). You don't have a full 1 GB of potential storage, you have 2 sections of 512mb with the same data on both. This is how Crossfire and SLI work, this is how parellel GPU's work as well, so far as I know.
 
hermeslyre said:
The memory still doesn't add up, if we're talking 512mb X2. Both cards are working to render the screen right? They both need the meshes, textures, vertices, all the geometrical data loaded into the VRAM.. they both need an exact mirror of the other to get their work done. It's like a RAID 1 array, what's stored in one drive is stored in the other(s). You don't have a full 1 GB of potential storage, you have 2 sections of 512mb with the same data on both. This is how Crossfire and SLI work, this is how parellel GPU's work as well, so far as I know.
Click to expand...

So whats the point then?
 
Tried to explain it in the above post, it's simply needed to be done like that. If you removed 512mb off one card, that card wouldn't work. They both need the memory, but they can't be used individually, they work as mirrors to render the frames as they come to them.
 
hermeslyre said:
The memory still doesn't add up, if we're talking 512mb X2. Both cards are working to render the screen right? They both need the meshes, textures, vertices, all the geometrical data loaded into the VRAM.. they both need an exact mirror of the other to get their work done. It's like a RAID 1 array, what's stored in one drive is stored in the other(s). You don't have a full 1 GB of potential storage, you have 2 sections of 512mb with the same data on both. This is how Crossfire and SLI work, this is how parellel GPU's work as well, so far as I know.
Click to expand...

i THINK that the rendering is actually split between the memory, so half is rendered with one set of memory modules and the other half uses the rest of the memory.

i mean, they are rendering the same picture, yes, but completely different parts of it.
 
That's the only other explanation, I agree. The only problem I see: it would presume some mighty software coding, which in an industry that's still on it's head regarding multithreading, doesn't seem as likely, and that SLI and crossfire are capable of the same thing, as well as several other rendering processes; one rendering one part, vice versa, and doubled VRAM is still not a feat considered feasible.
 
Why don't you run some benchmarks and see, if the score is only similar to that of a single 3870 then theres a problem, if not then it's working fine.
 
[-0MEGA-];909684 said:
Why don't you run some benchmarks and see, if the score is only similar to that of a single 3870 then theres a problem, if not then it's working fine.
Click to expand...
How does one do this.
 
I downloaded 3dmark and my score was 12,900. The cpu test seemed like it was pretty bad. I have q6600 quad core and i was getting like 1fps on the cpu test, is it suppose to be like that lol?
 
yeah even 3dmark 03 will drop to 1FPS with my e4500 overclocked, i guess its just a really hard test for processors...
 
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