Reader Review: XLR8 300/200/1MB G3 CPU Upgrade

For under $1000, my aging Power Mac 120 has entered the " G-3 Age", zooming along at 300 Mhz..thanks to my new Interex Mach Speed 300 G-3 Processor card from Small Dog Electronics.

The unit comes packed in a very commercially-acceptable purple, black and white box...with all the appearance of a very cool looking hi-tech toy.

Inside, you're shocked to see what appears to be an empty box. But the goodie's just under the packing which sits between some upside down cardboard hiding the real prize.

A dangling anti-static wrist strap in the box can throw you off though. Whats this weird looking wire I'm supposed to attach to my body?

You don't find out until you dig through the manual to find it's protection against the un-initiated frying their computer from a static electrical discharge.

I've always subscribed to the "touch the power supply...and then a grounding screw on an electrical plug to ground yourself" school..and since I have no carpeting, and tile floors...I don't get much static in my life...except for the static cling outta the dryer with my socks!

The manual is a bit confusing. You get some general information about the product at first, then some arcane language about its' "Multiple Variable Processing"..then an installation section with some general instructions and then specific language for different type of Mac installations.

First dilemma: Do I have L1, L2, or L3 cache in my old 8500? Ok...Tech Tool Pro tells me I have L-1 and L-2.....and the manual talks about L-3 too, and I'm real confused. [The L3 cache the manual refers to is the stock motherboard Level 2 cache that becomes L3 (Level 3) cache after the G3 card is installed, since it has its own L2 backside cache on the card-Mike]

Lets look under the hood.
I've felt the pain of opening up my 8500 before to add Ram.....Ease out the cover screws, slip off the tight fitting case...slide out the processor card....unhook all the motherboard connections, unscrew the motherboard , take a deep slow breath, and carefully slide it off its attachment clips. [See my 8500 Cache Upgrade tutorial for a illustrated guide-Mike]

Major Surgery! But after getting down to the motherboard, where oh where is the cache located? [Between the Dimm RAM slots - as shown on step 4 of my tutorial-Mike]

I found it, but got confused...was it L-1 or L-2, and did it make a difference?

I decided to ignore the problem and re-assembled my system, but this time gently easing in the new G-3 card.

Screw everything up again, and then I read a little further in the manual. Then I find...."You could have an TQFP card or not" , and it makes a difference. [TQFP is the cache chip package type (Thin Quad Flat Pack)-Mike]

While the manual describes how to tell if its a TQFP card....it doesn't tell me what it is...or why I should care. I was confused, but I forged ahead anyway.

I was brave and booted up the system. To my amazement...it fired right up. But the backside cache wouldn't run, and I noticed the software-setup again asked about the TQFP designation.

I vamped a little and gave it an answer I didn't really know ( not much different from some college chemistry tests I've taken) and sat back to see what happened.

It ran slowly...but without the cache activated and I knew something was wrong....and it was either operator cache error or wrong TQFP.

Back to the case...opening everything up.....unzip...unplug....and take another look for the cache thing.

That's when I saw the small Dimm in the cache slot. But was it L-1 or L-2? At this point I didn't really care...I took it out and hoped it was the right offending cache dim.

As I zipped everything back up...I took a closer look at the G-3 Card to see if I could find the TQFP. The instructions told me to look for some silver square rectangles opposite the heat sink. There weren't any, so I figured it wasn't a TQFP card. I hoped life would go on and for the first time...I got my wish.

After closing up the case again and firing it all up I held my breath.

The screen came to life. The extension icons slowly lined up...and it was actually running! I loaded up the software, and set up the TQFP setting as if I knew what I was doing and it actually told me the 1-Meg backside cache was running. Another click and backside cache would automatically be installed on the next boot-up.

And I was up and running in the G-3 zone. I expected system hangs, type 11 errors, and frozen programs but everything from Soft Windows to Netscape, to Mac Bench to Tech Tool Pro worked fine, of course at a much faster speed.

Netscape scrolled so fast...I couldn't keep up with the information. My old 604 ( not even a 604 E) scrolled slow by comparison.

Softwindows actually zipped along too for the first time. And it was all rock-solid and stable.

OK lets talk benchmarks.....

• MacBench 4.0: 1074
• Norton: 370 Mhz
• Tech Tool Pro: 299 Mhz
• Apple System Profiler: 333 Mhz.