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RadeonHD 6570 1GB shows 85MB free?
Posted: Wed Nov 07, 2012 10:01 am
by Deniil
Hi
The WB title bar shows I have about 80-90MB free gfx RAM in normal usage of my 1GB RadeonHD card, just like it did with my 256MB Radeon9250 card in the XE.
I was just wondering if the 128MB gfx mem limit still applies even to GB RadeonHD cards?
I don't think I've ever run out on 128MB but it would still be nice to be able to use all 1GB of the card.
Is it an address range issue of AmigaOS? Unable to map the gfx card in the upper 2GB range? Is it even memory mapped?!
Re: RadeonHD 6570 1GB shows 85MB free?
Posted: Wed Nov 07, 2012 10:17 am
by Slayer
The limit is 256MiB but I paste from Hans - don't worry about the 207 MiB reference it tends to be different depending on the Users settings - for example I have 225 MiB free at the moment even with OWB open etc
A little strange why you only have 128 MiB, perhaps your workbench prefs string settings reflect memory used not free? or your card isn't identified correctly? Just guessing since you have 1GB
Hans wrote:
The 256 MiB VRAM is due to Picasso96 assuming that the CPU has direct access to all VRAM. With newer graphics cards only the first 256 MiB is directly accessible over the PCIe/PCI bus, as otherwise your VRAM would take up too much address space (for 32-bit processors). The rest of the VRAM is only directly accessible by the GPU itself. As a consequence, Picasso96 will only ever know about the first 256 MiB. Not to worry, 3D graphics drivers will be able to access the rest.
Why 207 MiB free? Well, to start with the graphics driver reserves some space for its own use (for shaders, command packets, etc.). The Workbench screen that you're looking at also takes up VRAM, as does all of the icons, theme bitmaps, or any other bitmap currently being used. High resolution graphics takes up a lot of space.
Re: RadeonHD 6570 1GB shows 85MB free?
Posted: Wed Nov 07, 2012 2:08 pm
by ChrisH
Slayer wrote:A little strange why you only have 128 MiB
Presumably his Video RAM is not one contiguous chunk, but several separate chunks of 128MB. On 256MB cards this was quite common, but I don't know if it is common on cards with larger RAM. Picasso96 can only handle one chunk of contiguous video ram.
But as Hans' (quote) says, the GPU (and so any 3D implementation e.g. Gallium 3D or Warp3D) will be able to use all of the Video RAM.
Re: RadeonHD 6570 1GB shows 85MB free?
Posted: Tue Nov 20, 2012 1:41 am
by AmigaDave
ChrisH wrote:Slayer wrote:A little strange why you only have 128 MiB
Presumably his Video RAM is not one contiguous chunk, but several separate chunks of 128MB. On 256MB cards this was quite common, but I don't know if it is common on cards with larger RAM. Picasso96 can only handle one chunk of contiguous video ram.
But as Hans' (quote) says, the GPU (and so any 3D implementation e.g. Gallium 3D or Warp3D) will be able to use all of the Video RAM.
Interesting!
So everyone using AmigaOS4.1.5 has access to only the first 256mb of VRAM (if the VRAM has at least one contiguous chunk of VRAM of that size), but when 3D drivers are commpleted, they will be able to use all of the VRAM on our 512mb, 1gb or 2gb video cards?
That is good to know, if I am understanding what you wrote correctly.
Re: RadeonHD 6570 1GB shows 85MB free?
Posted: Thu Nov 22, 2012 4:12 pm
by ChrisH
@AmigaDave
256MB should be *more* than enough for any 2D stuff you can think of. And if 256MB does somehow run out, them Picasso96 will gracefully handle that (storing currently unused bitmaps in non-video RAM).