Memory Upgrade for Mac Pro 1,1

Hello,

I have what I believe is a first generation Mac Pro. The system profiler says it's version 1,1.

When I bought it, I had an additional 2 GB of ram installed by the dealer for a total of 3GB.

Today I am trying to install a pair of 2GB DIMMS for a total of 7GB.

I bought the memory at my local mac dealer (Mac Enthusiasts in West LA). He asked what version of Mac I had and I said I thought it was first generation. He asked for the serial number, but I didn't know I needed one. I did however bring the manual and told him the date was 2006.

He assured me he had the right memory for my machine, despite my offering to get the serial number from home.

The point of all this is when I opened up my mac to install the memory, I was surprised to see that the original factory memory had HUGE BLACK HEAT SINKS on it. The second, dealer-installed memory had SLIM SILVER HEAT SINKS, and now finally the memory I bought today has NO HEAT SINKS WHATSOEVER.

Is it possible that memory technology has improved and newer DIMMS run cooler and don't need heat sinks? Or do I have the wrong memory? Is there any online guide or utility I can use to determine if I can use these modules?

Finally, here is the text on the sticker of the modules:

2GB PC2-5300 (667Mhz) DDR2 DIMM

The chips themselves appear to say "Lynnix" KOR

Please help.

Thanks,
P-FO