Found the 50MHz bus switch on Alchemy (5400/6400)
- Thread starter obsolete
- Start date
alectrona6400
Well-known member
oh sweet, thank you so much for the ebay link! yeah i can figure out the smd mounting situation just fine, lol... im doing this to a 6400/180 board, would it also be a good idea to change the multiplier for the CPU clock speed? otherwise i believe this runs at 225mhz now (at least until sonnet's extension loads)..
Fizzbinn
Well-known member
Sure thing.
Yeah, @obsolete mentions this in their first post, switching the resistor config from x5 to x4 to not overclock the onboard 603ev on their 5400/200. On my 6360/160 I think I'll change it to x3.5, 175MHz, as 200MHz seem like it might be pushing it too far but I like the idea of trying a little 603e boost even if I'm normally using an L2 G3 upgrade card. On a 6400/180, changing to x4, 200MHz, would be similar.
FYI - If you are looking for some of these tiny "0603" SMD resistors you can get a variety pack that includes the values here and a lot of others pretty cheap on Amazon:
Chanzon 1200pcs 0603 SMD Resistor Kit 0-10M Ω ohm 60 Values (Each Value 20pcs) - $8.59
Yeah, @obsolete mentions this in their first post, switching the resistor config from x5 to x4 to not overclock the onboard 603ev on their 5400/200. On my 6360/160 I think I'll change it to x3.5, 175MHz, as 200MHz seem like it might be pushing it too far but I like the idea of trying a little 603e boost even if I'm normally using an L2 G3 upgrade card. On a 6400/180, changing to x4, 200MHz, would be similar.
| CPUClock w/40MHz Bus | CPUClock w/50MHz Bus | Config | R332 | R331 | R330 | R329 | R145 | R144 | R143 | R142 | Note |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 80MHz | 100MHz | x2 | i | R | i | i | R | x | R | R | |
| 100MHz | 125MHz | x2.5 | i | R | R | i | R | x | x | R | |
| 120MHz | 150MHz | x3 | R | i | i | i | x | R | R | R | |
| 140MHz | 175MHz | x3.5 | R | R | R | i | x | x | x | R | |
| 160MHz | 200MHz | x4 | R | i | R | i | x | R | x | R | |
| 180MHz | 225MHz | x4.5 | i | R | R | R | R | x | x | x | * |
| 200MHz | 250MHz | x5 | R | i | R | R | x | R | x | x | * |
| 220MHz | 275MHz | x5.5 | R | i | i | R | x | R | R | x | * |
| 240MHz | 300MHz | x6 | R | R | i | R | x | x | R | x | * |
- R = Resistor in place
- x = No resistor in place
- i = Does not matter if there is a resistor or not
- R329 = 473 (4.7KΩ)
- R330 = 473 (4.7KΩ)
- R331 = 473 (4.7KΩ)
- R332 = 473 (4.7KΩ)
- R142 = 510 (51Ω)
- R143 = 510 (51Ω)
- R144 = 510 (51Ω)
- R145 = 510 (51Ω)
FYI - If you are looking for some of these tiny "0603" SMD resistors you can get a variety pack that includes the values here and a lot of others pretty cheap on Amazon:
Chanzon 1200pcs 0603 SMD Resistor Kit 0-10M Ω ohm 60 Values (Each Value 20pcs) - $8.59
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GeekDot
Well-known member
Just saw your mentioning now... thanks for the heads-up and I'm always happy when my
alectrona6400
Well-known member
just performed the mod... feeling lucky enough to leave my 6400/180's 180mhz 603ev at 225mhz (have not tested yet) even though i'll be using an upgrade card... also, i should ask... has anyone looked into modifying the memory slots to take 3.3v sdram? not sure if the pinout is much different but i would love to have more memory that would also be faster. though i know the types don't appear the same... unfortunately my 64MB dimms are dead, causing my system to have issues... quite sad. (and if anyone is willing to sell a couple of their 64MB or even 128MB 5V DIMMs to me, let me know, i'm in the US)
on a slightly less related note, how does one get better at BGA soldering.... would love to upgrade the CPU on my crescendo L2 to a G3 (copper) so it can do 400/500mhz. i tend to rush things which is an issue, and the bga equipment i got doesnt seem to do the job, so i'm curious about what stencils and materials work best for that kind of work. i already upgraded the L2 cache from 512KB to 1MB which yielded a nice performance boost, now close to the powermac G3 at 300mhz.
on a slightly less related note, how does one get better at BGA soldering.... would love to upgrade the CPU on my crescendo L2 to a G3 (copper) so it can do 400/500mhz. i tend to rush things which is an issue, and the bga equipment i got doesnt seem to do the job, so i'm curious about what stencils and materials work best for that kind of work. i already upgraded the L2 cache from 512KB to 1MB which yielded a nice performance boost, now close to the powermac G3 at 300mhz.
Fizzbinn
Well-known member
Finally got the time to work on this with a Performa 6360/160. Did the 50MHz clock crystal oscillator swap, and the bus speed memory timing resistor changes. Thought I'd give it a go leaving the CPU multiplier unchanged at 4x, meaning overclocking the CPU to 200MHz, it chimed but perhaps unsurprisingly I couldn't get it to boot all the way to the desktop before it would lock up.
To be really conservative (and since it was only one resistor change, an add) I backed it down to 3x, 150MHz, and it seems happy there, System Profiler, Sonnet Metronome, and Gauge Pro all show the Bus speed at 50MHz and CPU at 150MHz.
To get to the CPU multiplier resistor (R143) I needed to remove the heatsink, and ultimately redo the thermal paste so took a picture of the CPU, an IBM 603ev (PPC603evFB160r) that doesn't like a itty bitty little 25% overclock...
Going to ultimately try 3.5x, 175MHz, after I do some benchmarks.
I have to say working with 0603 resistors is kind of insane, no way I could do it without a microscope. I also got to use a new Christmas present that was extremely helpful, a SEQURE HT140 2-IN-1 Portable Hot Tweezers Soldering Iron. Used lots of Chip Quik flux too.
To be really conservative (and since it was only one resistor change, an add) I backed it down to 3x, 150MHz, and it seems happy there, System Profiler, Sonnet Metronome, and Gauge Pro all show the Bus speed at 50MHz and CPU at 150MHz.
To get to the CPU multiplier resistor (R143) I needed to remove the heatsink, and ultimately redo the thermal paste so took a picture of the CPU, an IBM 603ev (PPC603evFB160r) that doesn't like a itty bitty little 25% overclock...
Going to ultimately try 3.5x, 175MHz, after I do some benchmarks.
I have to say working with 0603 resistors is kind of insane, no way I could do it without a microscope. I also got to use a new Christmas present that was extremely helpful, a SEQURE HT140 2-IN-1 Portable Hot Tweezers Soldering Iron. Used lots of Chip Quik flux too.
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Fizzbinn
Well-known member
I think these Norton System Info v5 Benchmarks are pretty interesting:
All tests done in a Performa 6360/160 chassis (including with the 6500/225 board), same 64MB EDO DIMM installed on the logic boards and booted from the same Mac OS 8.6 install on a 160GB PATA HD.
My takeaways:
I wanted to compare the Performa 6360/160 vs. Performa 6360/150 (with 50MHz bus) with a 256KB L2 cache installed but I'm not able to boot the Performa 6360/150 with the cache installed, I get a start up chime but no video. Tried two different cache modules but no luck. Curious, @obsolete did you try your PM 5400/200 (with 50MHz bus) with a 256KB L2 cache installed? (I imagine it likely came with one?)
All tests done in a Performa 6360/160 chassis (including with the 6500/225 board), same 64MB EDO DIMM installed on the logic boards and booted from the same Mac OS 8.6 install on a 160GB PATA HD.
My takeaways:
- Going from a 160MHz 603ev on a 40MHz bus to a 150MHz 603ev on a 50MHz bus is overall a wash.
- At the ~same CPU clock speed the main benefit of the 50MHz over 40MHz bus is video and disk performance.
- The benefit is there is greater if you have a G3 upgrade (20% improved video performance)
- The 6500/Gazelle logic board's improved graphics aren't matched by Alchemy at 50MHz (not that surprising)
I wanted to compare the Performa 6360/160 vs. Performa 6360/150 (with 50MHz bus) with a 256KB L2 cache installed but I'm not able to boot the Performa 6360/150 with the cache installed, I get a start up chime but no video. Tried two different cache modules but no luck. Curious, @obsolete did you try your PM 5400/200 (with 50MHz bus) with a 256KB L2 cache installed? (I imagine it likely came with one?)
I think I did run it at 50x4=200MHz with the 256KB L2 cache, but I don't have any records. I'll double check the next time I have the machine out.
