Actual Benefits of Kansas w/ CPU Upgrade

[istar1018]

So, everyone says that the Kansas-based x600s are much better than their Tsunami-based brethren. A quick search has told me that:

-Kansas machines can support the coveted 604ev CPUs

-Kansas machines don't have L2 cache soldered on the motherboard

-Kansas machines don't have problems with G3 upgrades and speculative processing.

My question: I'm planning to put a G4 CPU upgrade in a 9600. Would there be any benefit from using a Kansas machine over a Tsunami machine? This seems to negate the 604ev and L2 cache issues. Are there any other issues I should be aware of? Also, if anyone can point me in the right direction re: this speculative processing issue, I'd like to find out more about that.

Thanks!

 

[equill]

Without any intention of being censorious, I have to point out that chasing your own research data will be the best support for your decisions. That said, I admit that I have a 9650/G4/800MHz in use. It flies in OS 9.2.2, even given its 50MHz system bus speed. Why did I upgrade it? First, because I can, and second because it interests me to discover just how far the Mac systems can be pushed, short of large-scale case surgery or complete change of the innards with another system. A G4 CPU is able to re-confer the server-quality performance of the 604ev that is lacking in the G3 CPUs.

Having several native G4 machines, I have not been impelled to use OS X on any of my G3/G4-upgraded 9600 or Beige G3 Macs. However, it may be of use to you to know that you may be able to get a G4-upgraded 9600 to support Leopard (with XPostFacto, of course). With G3 upgrades, you may be limited to Tiger.

Here is a contemporary appreciation of the 9600/Kansas Mac before and after upgrade.

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[equill]

Some further information about SP is here and here.

de

 

[trag]

My question: I'm planning to put a G4 CPU upgrade in a 9600. Would there be any benefit from using a Kansas machine over a Tsunami machine? This seems to negate the 604ev and L2 cache issues. Are there any other issues I should be aware of? Also, if anyone can point me in the right direction re: this speculative processing issue, I'd like to find out more about that.

I'm not sure that it negates the L2 cache issue. One of the issues with the motherboard L2 cache is that its presence can slow the maximum bus speed achievable. If you're going to run your G4 at a standard 50 MHz or below, this is unlikely to matter. If you're going to push the bus speed, then it could matter.

Apparently, removing resistor R31 on the 9500/9600 disables the L2 cache on the motherboard, so that is a route one can take if one does not have a Kansas board. I would double check my resistor designation before trying this. I'm flying on memory alone here.

Most CPU upgrades have some method to deal with speculative processing, and I believe, that is only an issue with G3 processors, not with G4 processors, but I may be mistaken.

In any event, the speculative processing issue is dealt with in software/firmware by the upgrade vendors and it doesn't cost much performance. If you simply must compulsively have that last percentage or two of performance, then you need a Kansas machine (although tests indicate memory throughput may be slower) or you can replace the ROM chips on a 9500/9600 board with Kansas ROM chips which gives the speculative processing fix.

Use 8 Mbit 44 pin PSOP Flash chips which are rated at 90 ns or faster for the ROM replacements. They were/are available from a variety of manufacturers. The main issue is that some of them have a Reset pin which must be tied high for proper operation (run a little wire from 5V to the pin).

The other main issue is getting a 44 pin PSOP adapter for a chip programmer so that you can program the Kansas ROM contents onto the Flash chips...

Alternatively, the Flash/ROM chips can be installed on a ROM DIMM, but few people have the necessary circuit board available (the ROM board from a Power Computing machine can be adapted).

 

[istar1018]

Thanks everyone!

The adjacent thread has certainly pointed out some pitfalls of the Kansas-based machines & G4 upgrades. Methinks I'll stick with my Tsunami, and maybe explore ROM making, as trag suggests, so then I could test this further.

 

[defor]

I did a little testing this morning and 9.2.2 seems stable on the 9600 + 1ghz, but 8.x and before (even the stock 9600 install from the cd, seem really flaky.. maybe apple changed something in the 9.x era for supporting real g4's that might help.. i know their target audience was os9 and unsupported x users...?