OWC ram install - light blinking - help please

[leftPCbehind209]

Sorry in advance for the noob question. I bought 16gb (2 x 8gb).

I followed the instruction verbatim from OWC site and from Apple site.

After removing all three original 1gb sticks, I inserted the first two 8gb sticks into slots 1 & 2 and then in slots 3 & 4 placed the 1gb sticks that came w/ computer originally.

Once I turned power on, the light above power button flashing quickly, nothing on screen.

What should I do?

 

[JavaTheHut]

8Gb registered RAM is not to be mixed with other ram of differing capacity pull out the 1GB ram sticks and reboot

Did you read this warning:? http://eshop.macsales.com/item/Other%20World%20Computing/1333D3MPE8GB/

 

[leftPCbehind209]

8Gb registered RAM is not to be mixed with other ram of differing capacity pull out the 1GB ram sticks and reboot

Did you read this warning:? http://eshop.macsales.com/item/Other World Computing/1333D3MPE8GB/

Thanks for the help. Didn't see that warning beforehand. I started a thread earlier re: the 16gb OWC ram purchase and said I'd be putting in two 1gb sticks in 3 & 4 and nobody said anything about it...I figured many on this board have the 8gb sticks and had done the same.

By the way, the install video on OWC's site says you can put back in the original RAM (I clicked on the 2010 Mac Pro memory install video). Stupid video.

 

[vogelhausdesign]

So just curious here, is it better/faster to get 8gig sticks or is it the same to get 4gig sticks. Is this issue only for 8gig modules by the way?

 

[leftPCbehind209]

So just curious here, is it better/faster to get 8gig sticks or is it the same to get 4gig sticks. Is this issue only for 8gig modules by the way?

It doesn't look like the 4gb sticks have the same issues: http://eshop.macsales.com/item/Other World Computing/1333D3W4M12K/

However, I got the 2 x 8gb sticks because I only have 4 slots in my hex and want to be able to be at 24gb within a year (without having to discard 4gb sticks).

 

[vogelhausdesign]

Ah, makes sense I didn't read you had a hex. I wonder if there is some reason why though? Is their any benefit to having their 8g modules other than saving space and maxing out?

 

[JavaTheHut]

Ah, makes sense I didn't read you had a hex. I wonder if there is some reason why though? Is their any benefit to having their 8g modules other than saving space and maxing out?

What I understand within my limited knowledge is registered RAM CAN NOT be mixed with Non registered RAM combining would create problems?. At this time it seems 8GB RAM sticks can only be found as registered, reason being is they are primarily used in servers where error checking is needed.
Regarding speed I have read that registered RAM is slightly slower due to it checking for errors but as you mention "maxing out" you can fit a MP 6core 32GB of RAM or a 12core with 64GB.
Does it work you ask? - yes

 

[WardC]

You can mix 1GB, 2GB, or 4GB sticks, but not 8GB sticks. 8GB sticks have to be installed by themselves, and if you run 8GB sticks, you can ONLY run 8GB sticks, you can't mix them with other sized modules. This is the rule. Also you lose DDR3 dual and triple-channel RAM acceleration when you mix RAM sizes.

 

[WardC]

From the OWC page for the 16GB RAM upgrade (2 x 8GB modules):

"IMPORTANT OWC NOTE:

The OWC p/n OWC8566D3MPE8GB 8GB modules included in this kit require that all installed modules be of this same matching part. Other existing Apple or 3rd party 1GB, 2GB and 4GB modules are not supported for use with this kit and need to be removed when this kit is added."

http://eshop.macsales.com/item/Other World Computing/85MP3S8M16GK/

 

[SDvideoguy]

Also you lose DDR3 dual and triple-channel RAM acceleration when you mix RAM sizes.

I have 4 x 2Gig ram sticks in my early 2008 Mac Pro with the original 2 x 1gig sticks (10gigs total). I have had no problems, but have always wondered if this configuration has in any way hampered the speed of my system. Can someone shed some light on this for me, please?

 

[WardC]

DDR3 is only for the newer (2009) and later Macs I believe. The RAM is accelerated when you use 3 sticks instead of filling all 4 slots (or 6 slots instead of 8 on the dual processor models). You have to stick the RAM chips in the 3 slots farthest away from the processor, leaving the slot closest to the processor empty. I am not sure about the 2008 Macs, but you can do "About this Mac" to see if your RAM is DDR3. I hope this helps.