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[supernova777]

agreed

[supernova777]

i just had to switch some ram around as i have this old Abit BE6 motherboard from 1999 that i wanted to get 768mb of ram (The max available for this board) its a strange board it only has 3 slots for memory..
anyways i had 2 x 128 + 1 x 256 giving me 512mb total, but of course anything short of max is not enough;) lol

anyways this board did not accept any pc133 ram at all it will not post with pc133 at all.. so i had to steal some pc100 sdram from my newly acquired G3 450mhz.. and after some testing i found that this g3 is just fine with PC133 sdram... in fact it even worked with a few 512MB PC133 pieces althought they showed up as 256mb (half their real size) interestingly enough i also tried with some single sided 256mb pieces and they also worked but showed up as 128mb..

i just plugged those same peices into the G4 450mhz and it seems to recognize the full 512mb size of the larger chips.. im about to test if the g4 sees the whole size of the single sided 256mb modules, but i would guess that it does based on it seeing the full 512mb of the others.

re-summary of findings:
powermac g3 450mhz (rev 2) = ok with pc133 (clocks down to pc100 just fine, sees dbl.sided 512mb as 256mb, single sided 256mb as 128mb)

powermac g4 450mhz = ok with pc133 (clocks down to pc100 as seen in system profiler, sees dbl sided 512mb modules, also seems to recognize full size of single sided 256mb modules)

system profiler also showed the speed/timing of the downclocked pc133
some were detailed as pc100-222s
and some as pc100-322s
apparently 222s = cl2 ram?
and 322s = cl3 ram?
and from a google search the 222s ram is said to be faster


is there anything better then PC100-222s?
if 222s is faster then 322s, is there a speed of pc100-122s?


also one more note: i just put in 1 x 256mb PC100 module that was from my g3 450mhz and the g4 450mhz came back saying it was incompatible!
the ram itself has a sticker that says g3 or g4 yikes.. the g4 i have is not a yikes.. but im still wondering why its incompatible when its pc100 sdram and the g4 45mhz agp model is downlocking the other pc133 chips to be pc100! wierd;)

[supernova777]

whats the best way to test my ram? using Apple hardware test cd? or is there another app i can do thats like memtest for mac?
i dont think we have a apple hardware test posted for the AGP sawtooth.. ?? do we?

https://discussions.apple.com/thread/1929867
ok this post says there is not AHT for the sawtooth and that they only started that with the digital audio models..

heres a post showing all the ahts i think
http://www.info.apple.com/support/aht.html


whats techtool pro?
probably for X?

[MacTron]

TechTool Pro 3 have a RAM tests and VRAM (and many others test) ...

[SnakeCoils]

Hello, I join this thread to share my experience about memory setup on various MDD machines I have handled so far.

Well, I am gone thru an hard path trying to fill all the memory slot of my MDDs because results were different with different motherboard revision and here is what I have learned in my experiments:

Motherboard 820-1453-A (no extra fan plug near the modem PCB socket and no extra cooling aperture near the PCI slot end)

It accept almost all of the DIMM i put in, single and double sided, CL2, CL2.5, CL3, everything is not faulty from the beginning works perfectly for all the time. The full 4x512Mb configuration is handled flawlessly.

Motherboard 820-1476-A (extra fan plug near the modem PCB socket and extra cooling aperture near the PCI slot end)

It accepts only a percentage of the DIMMs that works on the previous motherboard and very difficult to have the full 2Gb configuration using 4x512 Mb. The only working setup was to put a couple of DIMM with timings 30330 in the first two slots (nearest the CPU) and a couple with timings 25330 in the other two (far from the CPU).
Otherwise the system is usually stable with 3 memory slot filled, when adding the fourth module the system, sooner or later will crash.

So far the most stable working and fastest system I have assembled has:

Motherboard PCB: 820-1453-A
CPU PCB: 820-1470-A (Dual 1.42 GHz overclocked to 2x1.50 GHz)
RAM: 2 Kit of Kingston KHX2700K2/1G HyperX couple (CL20220 on System Profiler) for a total of 2Gb (4x512 Mb)
GPU: ATI FireGL X3 flashed to X800XT (installing the ATI 9200 Hotfix under OS9 permit to recognize and use the full monitor resolution).
HD: WD Raptor 150 Gb with SATA/IDE bridge connected to MDD's internal ATA133 bus (snappier than every SCSI drive I have tried so far, including 15k)

It is rock solid, never freezed not in OS9 and not in OSX.

Recently I have purchased on eBay four identical 512Mb Corsair XMS2700 CMX512-2700LLPT and they also works without problems on the configuration above, they are only slightly slower than the Kingston HyperX (20320 vs 20220) but they perform almost the same, no noticeable differences in the everyday use. Of course I have put back the HyperX in MDD since I want the maximum speed possible.

The other MDD machine I have assembled (and mostly unstable with 4x512Mb RAM) is configured as follow:

Motherboard PCB: 820-1476-A
CPU PCB: 820-1452-A (dual 1.25 GHz on 167 MHz bus, not overclocked)
RAM: 2x512 Mb Infineon chips (latency 3)+ 1x512 Mb Micron chips (latency 2.5) +1x512 Mb Samsung chips (latency 2.5)
GPU: ATI Radeon 9000 Pro Apple OEM
HD: IDE Maxtor 20 Gb (Apple OEM) connected to internal ATA133 bus

In this setup the MDD is absolutely stable and no freezes occur under light or heavy load but every other memory combination I have tried failed miserably.

Of course I have also tested other CPU boards but every time with the same poor results:

PCB 820-1470-A (Dual 1.25 GHz on 167 MHz bus, not overclocked)
PCB 820-1497-A (Single 1.25 GHz on 167 MHz bus, not overclocked)

with the 820-1470-A CPU board plugged to the 820-1476-A motherboard the number of failures in RAM combination were even higher.

I have tried on this MDD also the HyperX modules and crashed, then Corsair XMS and crashed…

In the end seems (to me) that motherboards with PCB 820-1453-A can handle almost everything without glitches while the 820-1476-A are a truly nightmare to expand to maximum memory, the only working setup seem to put two slow DIMMs (CL3) in the J21 and J22 slots and two fast DIMMs (CL2.5) in J23 and J20 slots.

Anyone had better luck?

[supernova777]

http://lowendmac.com/2009/does-using-matched-ram-make-your-mac-faster-or-more-stable/

heres an article talking about this topic

claiming a slight performance gain from simply using the same brand/type of ram
very slight tho!

[supernova777]

oops wrong thread

[supernova777]

does the mdd support dual channel?

[Knezzen]

does the mdd support dual channel?

Nope