Looks like a real ceramic Pentium MMX but possibly someone cleaned it with a solvent which removed most of the white painted Intel MMX logo off. The burned in circle on top looks like someone used one of the Micron screw on Heatsinks with not enough thermal grease. Matches exact as http://www.cpu-world.com/sspec/SL/SL2S9.html.
If it runs slow maybe the L1 cache is bad or the BIOS does not work proper with that S SPEC.

And another way these 2.8V is MMX. Rest of non-mmx is usually 3.3V-3.45V.

Cheers,

3x sounds right, set it to 1.5x and it should internally run at 3.5x. If it does then it is an MMX. Make certain L1 (internal) cache is enabled in BIOS for performance issues.

See that "200" in the bottom left corner ? I suspect it was this kind of chip : http://www.cpu-world.com/CPUs/Pentium/Intel-P … BP80503200.html

It's the one Horum linked to. It had a glued-on heatsink by Intel originally attached. The "200" is in the corner so you can see the speed despite the heatsink. I own a 133 one, which is an exact match visually.

Deksor wrote on 2020-03-10, 07:11:

See that "200" in the bottom left corner ? I suspect it was this kind of chip : http://www.cpu-world.com/CPUs/Pentium/Intel-P … BP80503200.html

derSammler wrote on 2020-03-10, 12:26:

It's the one Horum linked to. It had a glued-on heatsink by Intel originally attached. The "200" is in the corner so you can see the speed despite the heatsink. I own a 133 one, which is an exact match visually.

I think this here is probably correct.
Perhaps (one of) the previous owner removed the heatsink when its fan went defective? Who knows 😜

OP, is the differently colored middle part also somewhat elevated? It could be residual glue. I'm not sure how easy (or hard) it would be if this is indeed the case.

http://www.cpu-world.com/sspec/SL/SL2S9.html

http://cdn.cpu-world.com/Images/uploaded/0000 … /L_00000605.jpg

Second link shows that CPU with the heatsink removed. It's exactly that CPU.

CapitanOdessa wrote on 2020-03-10, 00:54:

[...]

What is this thing supposed to be? When booted up, it says MMX200, but it runs super slow and horrible in the PcChips m530 motherboard it came with. I know it is definitely NOT a Pentium MMX200, because I have one and they look nothing like that. It doesn't even look like a real Pentium either, not even a common counterfeit Pentium rebranded as MMX! At least I know it has big PP beneath.

Super slow... that M530 doesn't have any L2 cache onboard, just a COAST slot. Is there a COAST stick in there? If not, that's why it's so slow: no cache.

CapitanOdessa wrote on 2020-03-10, 00:54:

No, not that cheap! https://i.imgur.com/FrG5pUr.jpg […]
Show full quote

No, not that cheap!

What is this thing supposed to be? When booted up, it says MMX200, but it runs super slow and horrible in the PcChips m530 motherboard it came with. I know it is definitely NOT a Pentium MMX200, because I have one and they look nothing like that. It doesn't even look like a real Pentium either, not even a common counterfeit Pentium rebranded as MMX! At least I know it has big PP beneath.

Anyway, does anyone know how to make this m530 motherboard recognise a real Pentium MMX233? I realised the max multiplier it has is x3, and MMX233 needs x3.5. When I plug it in, the POST screen shows 'Pentium MMX200' instead of the real name. I have a trusty (kind of) board PcChips M571 which I really like, and it works there! But it has the x3.5 multiplier. Before you say anything like 'lol don't use PCChips', for some reason is the only kind of motherboard you get in Argentina.

Wow, that is a weird posting.
So the BIOS says it's pentium 200MMX, it is marked as Pentium 200MMX, but you don't think it's a Pentium 200 MMX. Hmmmm.
What do you think it is? A 386SX @ 16MHz?

Did you try any other CPU in that PcChips m530?
If they are all slow, I guess the problem is the mainboard not the cpu.

Did you measure something on the PcChiops m530? Some benchmarks?

Thanks for the answers! So I thought I was in posession of one of the fake MMX's there are around, I had never seen one with this shape so I thought it was a fake. I'm happy to know it is not! And now I will try to see if the problem is the motherboard or something, the M530 is pretty slow, even in the BIOS settings, compared to other motherboards I have like M571 and M560 which have no COAST modules; that being said, I did not use any benchmarking tool to measure the real speed.

CapitanOdessa wrote on 2020-03-14, 15:33:

Thanks for the answers! So I thought I was in posession of one of the fake MMX's there are around, I had never seen one with this shape so I thought it was a fake. I'm happy to know it is not! And now I will try to see if the problem is the motherboard or something, the M530 is pretty slow, even in the BIOS settings, compared to other motherboards I have like M571 and M560 which have no COAST modules; that being said, I did not use any benchmarking tool to measure the real speed.

M560 and M571 both have onboard cache, probably 512kB, so they don't need a COAST stick. Your M530 doesn't have onboard cache, so it does desperately need COAST.

The M571 would probably perform similarly to the M530 with a COAST module, possibly even slightly slower. The M560 has the ALi Aladdin IV+ chipset, which is the fastest So7 chipset (clock-for-clock) bar none, so that will always win - although the M560 is hardly the fastest motherboard with that chipset.