WomBOOST - Very Small Performance Boost for your Wombat

[phipli]

This is a test release of a slightly underwhelming System Extension that tweaks the memory timings of a Wombat family mac to speed them up.

This extension should work on.... the 475, 476, 575, 577, 605, 610, 650 and 800.

Just to warn you, I only saw about 3% performance lift overall, although in some pure memory tests I saw about 14%. The CopyBits video tests also see reasonable gains.

This will not be any use if you are software overclocking your computer already and shouldn't be used at the same time as the 475 Overclock extension (fine with the control strip though). This should be most useful on 610s, 650s and 800s, although I have to admit I hoped for a bit more uplift.

Slightly unimpressive results from my LC 475 running at 25 MHz :

Usual caveats - what you do with your computer is your responsibility and not mine. While there is no reason why this should cause any harm to your computer (at all), if your computer stops working, please don't blame me! If you can't boot with the extension installed, hold shift to stop it loading and remove it from your Extensions folder.

 

[JDW]

Hi, @phipli !

A "memory timing" tweaker — very interesting!

I also see we defining the 475, 476, 575, 577, 605, 610, 650 and 800 as being the "Wombat family" of vintage Macs.

The file you graciously attached for us appears to be an alternative to using your excellent 475 Overclock software, and of course you say not to use them both at the same time. Pardon me for asking, but would you be able to explain why a Wombat Mac owner would choose WomBOOST over 475 Overclock? I'm just curious if there's a special use case for WomBOOST because you clearly spent time making it for a particular reason.

Thanks.

 

[phipli]

The file you graciously attached for us appears to be an alternative to using your excellent 475 Overclock software, and of course you say not to use them both at the same time. Pardon me for asking, but would you be able to explain why a Wombat Mac owner would choose WomBOOST over 475 Overclock? I'm just curious if there's a special use case for WomBOOST because you clearly spent time making it for a particular reason.

It isn't an alternative - it doesn't touch the clock speed.

Only the mini wombats, the 475 / 575s have the programmable bus clock.

why a Wombat Mac owner would choose WomBOOST over 475 Overclock?

If you have a 475 or 575, you wouldn't. If you have any other kind of Wombat, the 475 Overclock stuff doesn't work on them.

 

[phipli]

Folks, feedback from someone with a 40MHz 650 is that the extension actually slightly slows down CPU execution, so I suspect the apple RAM timings specifically are already quite tight. It did slightly speed up video though.

At some point I'll drag my 650 out and set it up, until then this is really just a very underwhelming proof of concept.

As above, it does create a small speed bump on a 475, but nothing compared to actually increasing your bus / CPU clock.

 

[eharmon]

Neat! I love the icon. For a big Wombat does this effectively boost the timings to match the 800 and mythical 40MHz configs in ROM, or are these custom?

MacWorld pegged the 800 at about 5% faster than a 650 (see below), so that seems pretty close to your results. (I know you know, but as a reminder for everyone else -- 800 was tuned for 60ns memory, 650 for 70ns).

Also, VRAM timings or just RAM?

 

[phipli]

does this effectively boost the timings to match the 800 and mythical 40MHz configs in ROM, or are these custom

Timings work that the faster your bus, the slower your timings generally, so what I've done is I've told it to use, for example, 25MHz timings when you're running at 33MHz, or 20MHz timings when you're running at 25MHz, assuming that you've not overclocked your computer and that your ROM is reporting the correct speed for the computer your are running.

This basically just runs the speed of the various memories (RAM, ROM & VRAM) with slightly more aggressive timings improving access times slightly.

I love the icon

I cheated really - I got AI to produce something, but it was a bit wonky so I spent a while in ReseEdit (mostly) fixing it. I'm still not happy with the rocket body itself (which I've already redrawn, but the perspective is off). It also forgot to draw a front left leg and the shading / colours weren't right. I generally just redrew bits I didn't like. Its how I normally do icons. You draw something rough and then squint at it and keep redrawing parts until its vaguely right.

With the shitshow about AI on 68kmla I'm not sure I should even mention that I used AI to start on it, but I prompted it at the end of the working day out of curiosity as I was about to finish work and start drawing the icon... and I liked what it made so used it as the basis of the icon. Not used it for icons before, I usually just draw my own. I've always enjoyed drawing icons.