GDDR2 on a video card would probably be a different technology from DDR2 (although it's not unlikely that many DDR2 cards are incorrectly referred to as GDDR2 and vice versa, the same happens with GDDR3/DDR3 and even GDDR5/DDR5 despite there not even being such a thing as DDR5).
On a graphics card, what you said is likely to be correct, but I have never heard of GDDR2 (which is a GPU-optimized memory interface) being used as a CPU's memory. Ehh, maybe I'm wrong about this, I'm just stating my experience.
I would like to see a link to these so called "GDDR2" modules.
GDDR is GPU VRAM only (always has been and always will be), so I really don't understand the confusion here or how GDDR anything could ever be mistaken for normal DDR RAM modules (since GDDR will always reside on a GPU).
OK, I just did a search for those exact modules and they appear to be for netbooks, and not for desktops, anyway (I still don't understand where they get off calling it GDDR2, but whatever).
Edit: I just saw a mention for a normal 240 pin version as well, but as far as knowing whether or not they're compatible with anything, your guess is as good as mine. I've never even heard of such a thing even existing until just now and it looks like only Elpida manufactures them (which makes me think something is WAY off somewhere).
and i just looked up my gddr2 ram, it exists, and the only diff between them and reg ddr2 is that the gddr2's create more heat due to running at a higher clock rate.
There are many differences between DDR1/2/3/4 and GDDR2/3/5, here are a few of them:
1- GDDR tends to run at much higher frequencies, about twice that of similar generation DDR
2- GDDR has much higher latency, 3-6 cycles longer due to deeper pipelining in the row register multiplexer
3- GDDR has different clocking requirements than DDR
4- GDDR has different data strobe signaling from DDR
The last two make GDDR physically and electrically incompatible with DDR control circuitry. Since no standard CPU/NB memory controller was ever made to use GDDR AFAIK, there has never been such a thing as GDDR DIMMs in recent history. You have to go back in time about 12 years for the last consumer cards that had proprietary DP-RAM or GDDR DIMMs for aftermarket upgrade.
There has never been such a thing as standard GDDR1/2/3/5 DIMMs.