iMac Memory does not work?

If the memory isn't bad then you did not install it correctly.

Judging from numerous reports on here, you either have incorrect speed RAM, or more likely, an issue with PNY RAM. Do the specs indicate that it is also compatible with 800mHz speeds?

Try pushing harder on each module with both thumbs to insure that they are fully seated in the slots.

Then if they are still not working, return the PNY and go with > OWC or > Crucial.

That model uses DDR2 667 MHz memory. 800 MHz memory was started with the 2008 models. According to MacTracker, anyway. 🙂

Agreed, but there have been several posts claiming new RAM to be compatible with 800mHz and 667mHz machines. As we know our Macs are particular about RAM speed. Sometimes one size does not fit all. This may be he case with the RAM the OP has purchased.

I'd have to agree with den.thed - return the PNY and order the correct RAM from OWC or Crucial. I've not come across a PNY product that any of my Macs liked (not even USB sticks).

I'm with stedman1

I've seen where PNY say's there OPTIMA RAM is compatible with everything from 400, 533 and 667 MHz bus speeds or 667 and 800 MHz bus speeds, in both there Spec's and on there packiging.

Example: > PNY OPTIMA 2GB DDR2 667 MHz PC2-5300 Notebook / Laptop

say's it's

Compatible with DDR2 PC2-5300 (667 MHz Bus Speed), DDR2 PC2-4200 (533 MHz Bus Speed), DDR2 PC2-3200 (400 MHz Bus Speed)

😕

😐 Well... they can't all be bad, because I have a couple of PNY Flash Drives and Camera Cards, that my Mac's like. 😉 😝 😁

LOL, neither of 3 Canon's (from inexpensive to expensive) even like PNY - it's Sandisk Extreme or better (pricey), but then I do a lot of HD video and there is definitely a difference in quality. Maybe I should re-phrase: I/this house do not like PNY.

OK I'll admit that none are recent purchases. I bought them 4 and 5 years ago when they cost 10 times more than the cheap little buggers they make today.