Compatibilty advice please

[Toke]

Need some advice please folks. I have just ordered these two items and now I'm wondering if I have made a compatibility mistake?

Asus M5A78L/USB3 AMD Socket AM3+ 8 Channel HD Audio ATX Motherboard

and a

AMD Phenom II X4 965 Black Edition 3.4GHz Socket AM3 6MB L3 Cache Cache 125W Retail Boxed Processor

I'm wondering if I should have bought a specific AM3+ CPU ? such as one of these:http://www.ebuyer.com/store/Componen...AM3+-Bulldozer

I'm thinking I will have to return the CPU and re-order? I read that AM3+ CPU's will fit into an AM3 Mobo (even though Asus won't support/garauntee such a thing), but the other way around ?!?

Thanks in advance for any advice.

[Toke]

Since posting I have now discovered that they are not compatible and have cancelled order of the AMD Phenom II X4 965 Black Edition 3.4GHz Socket AM3 6MB for an AM3+ to fit the Mobo. Apparently the AM3+ has 1 extra pin and pins are 6mm thicker than the AM3. Thanks to those who read with interest.

[gman863]

Originally Posted by Toke

Since posting I have now discovered that they are not compatible and have cancelled order of the AMD Phenom II X4 965 Black Edition 3.4GHz Socket AM3 6MB for an AM3+ to fit the Mobo. Apparently the AM3+ has 1 extra pin and pins are 6mm thicker than the AM3. Thanks to those who read with interest.

You would think that - with that big a difference - AMD should have used a different name for the "AM3+" CPU (AM4? Socket "Z"?).

This could confuse almost anyone, esp. since - if historical logic is used - the previous series (ex. AM2) would almost always work in the next newer series (ex. AM2+).

[Toke]

further info Yes Gman very confusing... it was a friend who oredered a complete uprade and wished me to assemble for him but after he ordered we noticed the conflict.. according to wikipedia it can be made to fit and have a Bios update ..But.. with one extra pin AND pins that are thicker I find just as confusing ... wikipedia info as follows.....

AM3+ is a modification of the AM3 Socket designed for CPUs which use the new Bulldozer microarchitecture and retains compatibility with AM3 processors.[8]

The AM3+ Socket specification contains a few noteworthy design changes over its AM3 predecessor. The 942-pin socket count for the AM3+ is an increase of one over the AM3 Socket's 941-pin socket layout.[9] The AM3+ Socket has larger pin socket diameter of 51 mm compared to 45 mm with the AM3 Socket. There is a faster serial link of 3400 MHz from the CPU to the power controller, compared to 400 MHz. The AM3+ Socket offers improved power regulation and power quality specifications, including an increased maximum current support of 145 A verses 110 A. There is also a redesigned CPU cooler retention harness allowing for slightly better airflow for CPU cooling, while retaining cooler backward compatibility

Some manufacturers have brought AM3+ support to some of their AM3 motherboards via a simple BIOS upgrade.[11] Mechanical compatibility has been confirmed and it's possible for AM3+ CPUs to fit in AM3 boards, provided they can supply enough peak current. Another issue is the use of the sideband temperature sensor interface for reading the temperature from the CPU. Therefore, some CPU PWM fan pins may only run at full speed. Also, certain power-saving features may not work, due to lack of support for rapid VCore switching.[12] Note that use of AM3+ CPUs in AM3 boards is not officially supported by AMD

Looking at the blown up socket's I can see where the extra pin will be situated, the M3 (lower left double blank) against the equivilant position on the M3+ board, So how do you get to put the M3+ processor into the M3 Board ??? http://en.wikipedia.org/wiki/Socket_AM3

[Digerati]

Whenever buying a motherboard, you should always ensure you buy a CPU listed on the motherboard's QVLs - qualified vendors list. Yours can be seen here. Note most boards, like this one, also include a QVL for RAM. There are too many RAM makers and models for motherboard makers to test them all. So while you need to buy CPUs from the list, you don't have to with RAM. You just need to ensure the RAM you buy has the same specs as listed RAM.

[scajjr]

The problem isn't the pins on the Phenom II X4 it's that the motherboard (and most microATX motherboards for AMD CPU's) have a top CPU wattage of 95 watts. So there ARE Phenom II X4's that work with that board, just can't be over 95 watts.

Sam

[Digerati]

Note the CPU Support List in the link I provided above. That "QVL", like the RAM QVL, lists the CPUs ASUS has tested and certifies is supported by that specific board. There are several 125W CPUs listed and at least one 140W.

That said, Sam is right. There are µATX boards that have lower limitations. This illustrates the point about using the QVLs. Just because a CPU fits the socket, that does not mean the motherboard (and/or chipset) supports it. It is also another reason to check out vendor's motherboard/RAM/CPU "bundles" - they do that homework for you - and guarantee it if you buy from them.

Back to the power issue, I think most of the boards released in the last few years don't have such limitations. I am certain of that for Intel boards, and pretty sure for AMDs.

The general trend over the last few years is shrinking motherboards (and computers). Yet today's users demand more of their computers and that takes more horsepower. It also takes more horsepower today to keep the badguys at bay and also Windows 7 itself, especially if 64-bit, can, and will put a lot of hardware resources to work. So motherboards need to handle that too. But not all 15" tires fit all 15" rims.

[Toke]

Yes indeed Digerati following your link there is so much more required info on the board, good tip for future buys.