DDR2 1066 only running at 800?

[crossed_wires]

Hey guys,

I just bought a new PC after being somewhat out of the loop for a couple years.
I ended up picking up the following:

AMD Phenom II 910 (quad core, 2.6 GHz)
Asus M3N72-D
Corsair DDR2 1066 (2x2GB)
WD Raptor 150GB


Anyway, I noticed that when I put the DIMMS at DIMM slots #1 and #2, at POST it will read "DDR2 800 MHz GANGED MODE" (not even sure what the hell ganged means)
If I move the DIMMS to #1 and #3, it reads "DDR2 800 MHz UNGANGED MODE"

First off, why are the DIMMS only showing as running at 800 MHz?
Second, what the heck is "Ganged" in relation to DIMMS? Never heard that term before.

Thanks and sorry if these are newbish questions....

Ryan

[Bobnova]

Ganging i don't know, but the speed thing is because the official RAM specs only go to 800, so anything over that has to be set manually in the bios on most boards.
Some boards can read extended ram profiles and auto-set things higher then 800, but not that many.
If you go into the bios you'll find memory speed options (on auto right now) that you can set to your ram's official profile.

[Spyguy]

"It is amd's version of Nvidia's Locked vs unlocked architecture.

basically allowing you to use your ram in dual channel vs single channel.

Ganged = dual channel mode for ram. All cores get access to 100% of the ram.

unganged = single channel. Each core gets access to a stick of ram.

In theory, the unganged mode is better as each core will get access to data quicker. In theory.

Some limitations apply... and i dont know muchelse.

Edit: sorry, it also alows you to control the clocks indipendantly from eachother. "


I didn't write this; all credit goes to danewfie at overclockers.net

Original Post

http://www.overclock.net/amd-memory/324052-ganged-vs-unganged-mode.html

It's amazing how much a google search can help.

[Bobnova]

Err, what about on quads? Or triples?

Not sure i buy that.


I thought nvidia's locked/unlocked was the option to isolate the ram clocks from the FSB clocks.

[mjw21a]

I know with my RAM I had to manually set it in the BIOS to run at DDR1600 instead of 1333. I daresay Bob's right with it being down to official RAM speeds.

[Ahgemon]

got 4 sticks of ddr2 pc8500 patriot ram, which ran at 1066 unstable on my old xfx780i board, until I cooled it down then it was ok.

Now I am using it in my current AMD build (in sig) and have had no such luck getting it to run at 1066 using a athlon 2 x2 250 (it has cpu limitation) or my current phenom 2 quad core.

it reads 800mhz ganged mode like your does.

in the BIOS under the memory option to adjust the ratio from 4.00 to 5.33, this sets it to 1066. however everytime I do, it won't post or do anything.

just retarded this stupid ddr ram won't run at its rated speed, I would gladly buy rambus but no one will carry it.

not sure if there is a way around the 800mhz nerf

[daytripper67mi]

Tony explains the ganged/unganged modes correctly here(tony is an ocz rep)
http://www.xtremesystems.org/forums/showthread.php?t=166222



Just some info for you guys.




ganged mode is 1x128bit dual channel

unganged is 2x64 bit dual channel

Some motherboards are reporting unganged as single channel at boot, this is not true, if you see anyone saying they have defective memory please point them to this post.

Ganged will give higher sandra bandwidth at this time than unganged, this is because sandra does not fully support phenom and is working in 1 thread mode. Once sandra supports Phenom unganged 2x64bit will take the lead

If you are running multi threaded benchmarks you need to be in unganged mode, this is the fastest way of running the system.

[bz2klag]

AMD Phenom II 910 (quad core, 2.6 GHz)
Asus M3N72-D
Corsair DDR2 1066 (2x2GB)
WD Raptor 150GB


Anyway, I noticed that when I put the DIMMS at DIMM slots #1 and #2, at POST it will read "DDR2 800 MHz GANGED MODE" (not even sure what the hell ganged means)
If I move the DIMMS to #1 and #3, it reads "DDR2 800 MHz UNGANGED MODE"

First off, why are the DIMMS only showing as running at 800 MHz?
Second, what the heck is "Ganged" in relation to DIMMS? Never heard that term before.

Thanks and sorry if these are newbish questions....

Ryan

Ganged is like conventional dual channel mode, where both channels
are tied together for an effective 128-bit bus, both channels operating
on adjacent addresses, and both must do the same operation read or write.
Unganged allows each channel to be used independently accessing non-adjacent
addresses, and doing different operations at the same time.

As for the 800 MHz question, it is likely that the motherboard does this
to ensure that you will be to initially POST when dimms are at JEDEC spec
voltage. You have to adjust to 1066 manually after ensuring that the
RAM is getting enough voltage to operate at that frequency. Otherwise,
with some modules, you'd never be able to POST in the first place to go
into BIOS and fix settings. It would be an RMA nightmare.