RX 560 - 896SP showing only 2GB of VRAM instead of 4

[HQi88]

So I managed to snag an interesting RX 560 on the cheap, the owner was selling it since it only had 2GB of VRAM.

As you can see, the stickers on the GPU indicate that this is a 4GB model. VisionTek sells both 2GB and 4GB models of this GPU.

Taking the cooler off, we can see 4x SK-Hynix H5GC8H24AJR-R2C VRAM chips. I have found this spec sheet but I am not sure how to interpret it. Does this card have 4GB of VRAM on the GPU motherboard or was it a 2GB card that was mislabeled?

If it does have 4GB of VRAM, would a vbios update fix this issue? I am also wondering if I would be able to unlock the extra gpu cores to turn this into a regular 1024SP card instead of 896

Edit: I used both GPU-Z and HWinfo to check the GPU. Both say it's an RX 560 - 896SP but I forgot to take screenshots

 

[MrCommunistGen]

Assuming the spec sheet you found for that SK Hynix GDDR5 is accurate, it would seem to indicate that those are 8Gb (Gigabit, not Gigabyte) chips. The sheet states that the chip is 256MX32 (where the "M" would usually indicate Megabit), and since 256Mbx32 = 8Gb, the spec sheet is consistent with itself (no contradictory info). Since 1 byte == 8 bits -> 8Gbit/8 = 1GB.

Based on that, it would seem that the card is physically equipped with 4GB of GDDR5.

That said, I wouldn't immediately jump to the conclusion that reflashing the card will make it address the extra VRAM (it might). There could be other factors at play.

Based on the specs for an RX560 (either 896SP or 1024SP) it should have a 128-bit memory bus resulting in 112GB/s in memory bandwidth. I'm curious if GPU-Z or any other tools show a 128-bit bus or a 64-bit bus. If any tools indicate a 64-bit bus, it could be that 2 of the memory channels on the GPU are disabled. If that's the case, I'm not sure what reflashing the card might make all the VRAM addressable.

Edit/Update for clarity:
2GB version of the RX560 would use 4Gb chips and have a fully populated 128-bit memory bus (4 chips). If your card shows a 128-bit bus, it could be as simple as the VBIOS only addressing half of the memory. But if it's only showing a 64-bit bus, it's likely that half of the memory channels have been disabled. If the GPU has disabled memory channels, that's a non-standard configuration of the RX560 and it could very well be that VisionTek sold that card with a harvested die and didn't bother to remove 2 of the 4 memory ICs when they assembled the card.
A possible scenario that'd yield such a card:
If they were working with a pool of GPU dies with randomly disabled memory channels, they'd have to figure out which two channels to populate on each board they manufactured. If they had a surplus of GDDR5 it might have made more sense for them to just manufacture all the cards with all 4 GDDR pads populated even though the GPU could only use two of them, just to avoid having to figure out precisely which two to populate.

I have next to no experience reflashing GPUs, so I'm pretty leery of it, and I'd just avoid it. But if you're comfortable with flashing, potentially bricking, and then recovering a GPU, then I'd be curious to see if a reflash would fix the issue.

 

[HQi88]

Based on the specs for an RX560 (either 896SP or 1024SP) it should have a 128-bit memory bus resulting in 112GB/s in memory bandwidth. I'm curious if GPU-Z or any other tools show a 128-bit bus or a 64-bit bus. If any tools indicate a 64-bit bus, it could be that 2 of the memory channels on the GPU are disabled. If that's the case, I'm not sure what reflashing the card might make all the VRAM addressable.

Well the bus width is 128 bit so I remain hopeful! Interestingly, GPU-Z says it has 1024 shaders, but using the lookup button and the box packaging it came it says it has 896 shaders

 

[eidairaman1]

View attachment 239588

Well the bus width is 128 bit so I remain hopeful! Interestingly, GPU-Z says it has 1024 shaders, but using the lookup button and the box packaging it came it says it has 896 shaders

I can interpret ram.
Mb is Mebibits/Megabits, Gb is Gibibits/Gigabits. MB is MebiBytes/MegaBytes, GB is GibiBytes/GigaBytes.

4 bits is a nibble (0.5 Bytes), 8 bits is 1 Byte.

8Gb is 1GB do you have a 4GB card, it is possible RX 560 cards to have 1024 SPs or be 896SPs and have 4GB ram

 

[HQi88]

I have next to no experience reflashing GPUs, so I'm pretty leery of it, and I'd just avoid it. But if you're comfortable with flashing, potentially bricking, and then recovering a GPU, then I'd be curious to see if a reflash would fix the issue.

For some reason it had the vBios of the 2GB version. After flashing the correct bios from TPU's archives, all 4GB of vram shows up.

 

[eidairaman1]

View attachment 239722

For some reason it had the vBios of the 2GB version. After flashing the correct bios from TPU's archives, all 4GB of vram shows up.

Either the wrong bios was put on the card by accident, or intentionally to meet sku quotas or possible that 2 chips were damaged.

You bought it used, so maybe owner put it on there for strange reasoning...

Hopefully the ram and remaining SPs after 896 are not damaged.

 

[Final_Fighter]

interesting

View attachment 239722

For some reason it had the vBios of the 2GB version. After flashing the correct bios from TPU's archives, all 4GB of vram shows up.

interesting that the memory is recognized as micron now.

 

[eidairaman1]

interesting

interesting that the memory is recognized as micron now.

It might be the resistor values.

Question is,is it stable, some register might of not been changed.