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by StillBored 1491 days ago
Man, that 6x86 CPU is still getting the short end of the stick nearly three decades later despite being a pretty solid chip.

So, first it generally had a higher IPC than anything else available (ignoring the P6). So, the smart marketing people at cyrix decided they were going to sell it based on a PR rating which was the average performance on a number of benchmarks vs a similar pentium. AKA a Cyrix PR166 (clocked at 133Mhz) was roughly the same perf as a 166Mhz pentium. Now had they actually been selling it for a MSRP similar to a pentium 166 that might have seemed a bit shady, but they were selling it closer to the price of a pentium 75/90.

Then along comes quake which is hand optimized for the pentium's U/V pipeline architecture and happens to use floating point too. And since a number of people had pointed out the Cx86's floating point perf was closer in "PR" ratings to its actual clock speed suddenly you have a chip performing at much less than its PR rating, and certain people then proceeded to bring up the fact that it was more like a 90Mhz pentium in quake than a 166Mhz pentium (something i'm sure made, say intel, really happy) at every chance they get.

So, yah here we are 20 years later putting a chip with what was generally a higher IPC than its competitors on a "shit" list mostly because of one benchmark. While hopefully all being aware that these shenanigins continue to this day, a certain company will be more than happy to cherry pick a benchmark and talk up their product while ignoring all the benchmarks that make it look worse.

Now as far as motherboard compatibility, that was true to a certain extent if you didn't bother to assure your motherboard was certified for the higher bus rates required by the cyrix, and the other being it tended to require more sustained current than the intels the motherboards were initially designed for. So, yah the large print said "compatible with socket7" the fine print later added that they needed to be qualified, and the whole thing paved the way for the super socket7 specs which AMD made use of. And of course lots of people didn't put large enough heatsink/fans on them which they needed to be stable.

So, people are shitting on a product that gets a bad rep because they were mostly ignorant of what we have all come to accept as normal business when your talking about differing micro architectural implementations.

PS: Proud owner of a 6x86 that cost me about the same as a pentium 75, and not once do I think it actually performed worse than that, while for the most part (compiling code, and running everything else including Unreal) it was significantly better than my roommates pentium75.

1 comments

6x86 PR200 was really fast in Linux of the day. The fact that it had 256 kB cache also helped.
Which brings up another fact, which was that microsoft disabled the cache on cyrix processor in one of the versions of windows NT (3.51 or 4?). And so you had to download a driver from Cyrix to turn it back on. But that didn't keep various people from claiming it's perf sucked in windows NT too.

IIRC the official excuse when this became public was that a MS engineer turned it off because one of their test machines couldn't complete a stress test with it enabled, but later it turned out the root cause was a bad motherboard. The curious part being that it didn't result in MS immediately issuing a hotfix to turn the cache back on.

edit: found one of the articles mentioning this. https://www.tomshardware.com/reviews/bananas,9.html

Apparently it was just writeback mode that got disabled, either way that link mentions a 30% perf hit.