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A20p/A21p/A22p motherboards

R, A, G and Z series specific matters only. NOT for AMD-Ryzen.
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MooNWalker
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A20p/A21p/A22p motherboards

#1 Post by MooNWalker » Wed Jun 19, 2019 5:49 pm

I found a place that still sells the subj. Problem is they've made a mess out of FRU numbers - e.g. an FRU for an A21p mobo (with Rage Mobility 128 and 16MiB video RAM) is assigned to a mobo for A21e with Rage Mobility M and 4MiB video RAM. Pretty much the only board that doesn't seem to have that mess is the board for A22p.

My understanding is that the difference between A20p, A21p, and A22p motherboards is pretty much just minor revisions, since they seem to have the same GPU with video RAM. The biggest differences between those machines (in stock configurations) are screen resolution (A20p is limited to 1400x1050) and CPU speeds, so it is perfectly fine to retrofit an A21p unit with an A22p motherboard, the only real difference will be that SMBIOS will report the model as changed from A21p to A22p. Is my understanding correct so far?

Things are a bit more murky between A20p and A21p/A22p, as I can see that while A21p and A22p appear to be using the same BIOS update file, A20p uses different BIOS update despite otherwise seemingly having essentially the same hardware.

Can someone please clarify for me the differences between these three machines and their motherboards?
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Screamer
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Re: A20p/A21p/A22p motherboards

#2 Post by Screamer » Tue Jun 25, 2019 11:23 am

MooNWalker wrote:
Wed Jun 19, 2019 5:49 pm
The biggest differences between those machines (in stock configurations) are screen resolution (A20p is limited to 1400x1050) and CPU speeds, so it is perfectly fine to retrofit an A21p unit with an A22p motherboard, the only real difference will be that SMBIOS will report the model as changed from A21p to A22p. Is my understanding correct so far?
Yes, as far as I am aware.
MooNWalker wrote:
Wed Jun 19, 2019 5:49 pm
Things are a bit more murky between A20p and A21p/A22p, as I can see that while A21p and A22p appear to be using the same BIOS update file, A20p uses different BIOS update despite otherwise seemingly having essentially the same hardware.

Can someone please clarify for me the differences between these three machines and their motherboards?
Here is my guess: the A20p uses a different BIOS image, because of how it uses SDR SDRAM instead of SDR SGRAM for its Mobility Rage 128 M3 graphics chip. I believe that SGRAM had a few differences in comparison to SDRAM, which may explain why the A20p's BIOS image was not shared between its newer counterparts.

The A21p and the A22p, used SDR SGRAM, and that might explain why they both share the same BIOS image. Take this information with a grain of salt, though. I am not completely sure if this is actually the case.

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