MP 1,1-5,1 Mac Pro 1,1/2,1: Using RAM without Apple-approved heatsinks, and with incorrect timings. Also, beware of no-name third party RAM

[EugW]

I'm in a weird but pleasantly weird situation. I had ordered 4x1 GB of OEM RAM for my 2006 Mac Pro, to add to my existing OEM RAM. However, there was a problem with my order. To make up for it, the seller not only gave me the RAM I asked for, the seller gave me an additional 4x4 GB RAM, for a total of 20 GB RAM.

The 4 GB RAM I originally ordered has the proper Apple-approved heatsinks, although it turns out they are faster spec'd than my Mac Pro needs. The extra 16 GB RAM does not have those huge OEM heatsinks, and is a mix of different brands and timings. I put all 20 GB in the Mac Pro and it all runs just fine.

My original Hynix RAM is 2 x 512 MB PC2-5300-555-11 (667 MHz) with the giant OEM Apple heatsinks.

The RAM I just got is as follows:

2 x 1 GB Kingston PC2-6400-555-11 (800 MHz) - Apple approved heatsinks
2 x 1 GB Hynix PC2-6400-555-11 (800 MHz) - Apple approved heatsinks
2 x 4 GB Kingston PC2-5300-555-11 (667 MHz) - standard heat spreader
1 x 4 GB Samsung PC2-5300-555-11 (667 MHz) - standard heat spreader
1 x 4 GB Micron PC2-5300-555-12 (667 MHz) - standard heat spreader

I was told the PC2-6400 RAM I got were pulls from Mac Pros, so I assume they were from MacPro3,1. I wasn't told anything about the other RAM but I'm not complaining because they were thrown in for free.

Am I correct to think that the minimum acceptable timings for a MacPro1,1 are 5300-555-11? I know it's 667 MHz PC2-5300, but I can't find that last 11 number listed anywhere. That means of all the above RAM, only the Micron RAM is out of spec (but still works fine). However, since the Micron RAM is out of spec and because it's an unmatched pair with the Samsung, I took those two out of the equation. I know it's not ideal having RAM that doesn't have the Apple-approved heatsinks, but after putting the RAM through its paces it's been 100% stable, so I'm willing to risk it as this is not my primary machine anyway. With my original 1 GB RAM, that leaves me with a total of 13 GB RAM which is a decent amount.

 

[EugW]

This is what the various types of memory look like:

 

[EugW]

I had purchased this RAM partially because the existing third party RAM in the machine I got all seemed bad. It was Wintec 4 x 2 GB = 8 GB server RAM without the large heatsinks and when I ran it with my Apple OEM Hynix RAM, or the 4 sticks by themselves, or either pair of 2 sticks by themselves, the machine crashed.

I had read somewhere that if there is no temperature sensor in the RAM, the Mac Pro's fan would go to max just in case, and stay there. However, the RAM never caused this to happen. The fans just always stayed at the minimum 500 rpm unless the CPUs got hot.

It turns out the RAM was simply overheating. I knew that already, but now I know why.

I installed Macs Fan Control and noticed there were no DIMM sensor readings. I assumed this was normal until after I received the RAM in the original post above. When I put the Kingston server RAM without the big heatsinks in, suddenly Macs Fan Control had temp readings for it, and showed that the Mac had ramped up the fan to idle around 850 rpm or so. This stayed consistent, in order to keep the RAM to 80C or below.

Then I removed that RAM and put in the OEM RAM, and saw that they had the temp sensors too, and would idle at about 43C with the fans back in at just 500 rpm.

I put the old RAM in with the new Kingston server RAM and now it seems to be fine, because the Kingston RAM keeps the fan moving. Here are some of the configurations I tried:

Fans at 500 rpm, no memory temp readings, Mac Pro crashes.
A1: Wintec
A2: Wintec
A3: -
A4: -
B1: Wintec
B2: Wintec
B3: -
B4: -

Fans at 500 rpm, no memory temp readings, Mac Pro crashes.
A1: Wintec
A2: Wintec
A3: -
A4: -
B1: -
B2: -
B3: -
B4: -

Fans at 500 rpm, no memory temp readings, Mac Pro crashes.
A1: Wintec
A2: Wintec
A3: Kingston
A4: Kingston
B1: Wintec
B2: Wintec
B3: OEM Hynix (big heatsinks)
B4: OEM Hynix (big heatsinks)

Fans at 500 rpm, no memory temp readings, Mac Pro crashes.
A1: Wintec
A2: Wintec
A3: OEM Hynix (big heatsinks)
A4: OEM Hynix (big heatsinks)
B1: Wintec
B2: Wintec
B3: Kingston
B4: Kingston

Fans at 500 rpm, memory at 40-45C, Mac Pro crashes.
A1: OEM Hynix (big heatsinks)
A2: OEM Hynix (big heatsinks)
A3: Wintec
A4: Wintec
B1: Kingston
B2: Kingston
B3: Wintec
B4: Wintec

Fans at 850-900 rpm, memory at 70-80C, Mac Pro is stable
A1: Kingston
A2: Kingston
A3: Wintec
A4: Wintec
B1: OEM Hynix (big heatsinks)
B2: OEM Hynix (big heatsinks)
B3: Wintec
B4: Wintec

Judging by touch, the Kingston RAM runs about as hot as the Wintec (or perhaps even hotter), but unlike the Wintec, the Kingston RAM has temp sensors. When placed in DIMM slots A1 and A2, the Kingston RAM tells the Mac Pro that the memory is running hot, and the fans ramp up to cool down the Kingston RAM which also cools the Wintec RAM down at the same time to keep the machine stable.

BTW, with Kingston RAM providing the temp settings, the fan speed difference is audibly noticeable, although mainly because the fan first ramps up to at boot, then it settles down after that. With the OEM RAM with the big heatsinks alone in the Mac Pro, it just stays quiet, with the fans never budging from 500 rpm. With the Kingston RAM in DIMM slots A1 and A2, at every boot the fans increase to about 1600 rpm and then gradually settle down to about 850-900 rpm as baseline.