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What is the fastest 486 upgrade chip?

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rorypoole

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what is the fastest 486 upgrade chip that will go in any 486 socket?

I have so far found
AMD 586 133mhz
Evergreen Technologies 586 upgrade chip

is there any faster in mhz or larger cache?
 
The Cyrix 5x86 (And thus, ST, IBM and TI labeled ones) are technically the fastest, though if you can find a 120MHz version you'll be lucky, they don't overclock well and they don't work with many motherboards.

Evergreen, Kingston and AMD are the same - but, the Evergreen TC has a voltage regulator onboard so is better for motherboards that only provide 5V or have no multiplier. Unlike the Cyrix M1 the AMD X5 isn't a real 586 and loses around 30-35% performance at the same clock - but overclocks better.

I don't believe the Kingston and Evergreens can be overclocked.

If your board can supply the correct voltage and multiplier, the AMD is your best bet, if it doesn't, go for an Evergreen.
 
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Kingston and Hypertec(also an AMD chip with 16k L1 cache) 586 upgrades for 486 mobos have 5v regs as well and generally go to 133MHz.
 
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It also depends on what your MOBO will support. Late generation MOBOs support advanced 80486s where early generation MOBOs will not. You could also consider installing Overdrive CPUs. I have a 80486 with a Pentium Overdrive: works pretty nice. :D

Also: MHZ is not the only performance enhancer: internal CPU cache is far more critical.
 
I wonder if someone has compiled a list of what "586" upgrades work with what 486 mobos. With the amount boards both "generic" and OEM I'd imagine It'd be a huge task.
 
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PeterLI said:
It also depends on what your MOBO will support. Late generation MOBOs support advanced 80486s where early generation MOBOs will not. You could also consider installing Overdrive CPUs. I have a 80486 with a Pentium Overdrive: works pretty nice. :D

Also: MHZ is not the only performance enhancer: internal CPU cache is far more critical.
Click to expand...

Overdrives are much more limited than the other upgrade chips.
Overdrives require an overdrive compatible socket, most the evergreen, AMD, and Cyrix chips can just drop in, even in some of the earliest 486 machines with a voltage/clock-multiplier adapter socket (which the evergreen ones usually had built in).

Agreed on Mhz, I know the Cyrix 5x86 100GP can out perform the AMD 5x86 at 120 in some tasks, with caching and some other extras in the Cyrix.
 
smeezekitty said:
AMD 5x86 150MHz but it is rarer then gold
http://www.cpu-collection.de/?l0=i&i=2520
Click to expand...

AMD made plenty of 150 and 160 MHz-rated 5x86 chips... they just sold them as "133 MHz" parts because they didn't want them to compete with their lackluster K5 chip.

Look at the three-letter code on the AMD 5x86 chip to determine its real speed rating:

ADW = 133 MHz
ADY = 150 MHz
ADZ = 160 MHz
 
IMHO, the best 486 for over overall use is the Am5x86-75+ADW. The "+" will take you to 150 MHz. Some (most) of the 75 ADW's will do 150 MHz anyway - at least mine do. The slot 3 Pentium Overdrive was a niche chip and will prove buggy in the long run. Other than a conversation piece, I don't feel the Cyrix is worth the time and effort. You might win a bar bet with the Cyrix stats, but when it come to actual day-to-day use (gaming) the Am5x86 wins hands down. What counts is if you can configure your mobo for a 50 MHz FSB and get it to supply the required 3.45 v.

(extracted from the Wiki)
[h=2]Models[/h]
CPUModel numberFrequencyL1 CacheFSBMult.VoltageTDPSocketRelease dateIntroduction price
Am5x86-P75X5-133 ADH133 MHz16 KiB33 MT/s43.45 V
PGA-168 Socket 1
PGA-168 Socket 2
PGA-168 Socket 3		6 November 1995$93
X5-133 ADY
X5-133 ADW
X5-133 ADZ
X5-133 BGC
X5-133 V16BGC
X5-133 W16BGC3.3 V
X5-133 V16BHC3.45 VSurface mounted 208-pin SQFP on PGA-168
X5-133 W16BHC3.3 V
X5-133 SFZ
Am5x86-P75+X5-150 ADW150 MHz16 KiB50 MT/s33.45 VPGA-168 Socket 1
PGA-168 Socket 2
PGA-168 Socket 3
 
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The Cyrix 5x86 is definitely faster than the AMD 5x86, if the motherboard and BIOS supports all of the Cyrix's advanced features, since it was a Pentium-class M1 CPU scaled down to fit a 486-class socket, while the AMD 5x86 is really just a 486DX with a 4X clock multiplier and more L1 cache. (The Cyrix gets even faster if you use special software to enable some of its extra features that are disabled by default because they were deemed to be unstable.)

But if you're installing it as an upgrade in an older 486 motherboard which was designed before the 5x86 even existed, then the AMD 5x86 will be faster due to its higher clock speed.
 
Great info in that thread!

Personally I really like the IntelDX4 OverDrive. It's a pretty fast chip, faster clock for clock compared to the 5x86 and works in more motherboards. If you really need more speed IMO you are better off looking at a Socket 7 platform.
 
I've always used the am5x86, but recently I am starting to prefer the Cyrix 5x86. I'm not sure why this is, but it seems to cooperate better with older motherboards than the AMD chip. I also agree that the Cyrix chip is faster if you can turn some of the advanced features on. At least on my system the Cx5x86-120 (features enabled) is slightly faster than the am5x86-160.
 
At 160mhz the AMD's do lose out to the Cyrix at 120 features enhanced, but at 150mhz the AMD will win... Yes, read that again.

The reason? What's the real bottleneck in a 486 class CPU's performance? Memory throughput. 160 and 120 are 40mhz FSB x4 and x3 respectively. The AMD 5x86 at 150mhz is 3x 50mhz. That 10mhz boost to bus speed REALLY delivers.

Just as a real 486DX/50 is about equal to a 486 DX2/66, and even faster at some tasks.

Hell, at 120mhz the AMD 5x86 actually ends up about equal in 'real world' performance to the 133mhz version -- since the latter is a 33mhz bus.

Kind of like comparing socket 1156 to socket 1150 on modern systems -- 800mhz vs. 1600mhz FSB, which is why the cheap IVY i5's pwn the previous generation i7's... and the current i7's (like my new 4770k) are just nucking futs.
 
Good luck getting your VLB/ISA to run at 1/2 divisor on a 50MHz BUS... :D

Oh, whilst I'm here, managed to pull off 273 in topbench with an X5 at 160MHz... Only ISA cards so no boost from PCI.
 
Memory performance on 486 boards is often slower at 50MHz than at 40MHz because of the added waitstates. I ran 3x50 for a while, but switched back to 4x40 because memory performance at 50MHz wasn't as good. VGA performance was great though...
 
Making the beast run at 200 MHz (50x4) is the one I want the most. No PCI staff, just VLB divided at 25 MHz if it doesn't work at 50 with 0 wait states. Cache and memory timings at lowest, (using memory that handles the overclock).
 
Running a 50mhz FSB is nice because things like your cache are extremely fast but the timings are so annoyingly tight.
 
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