How do you know if a mobo supports a specific CPU core/SOI/wattage?

[Alpaca Portrait]

I thought matching a CPU to a mobo was as simple as matching the socket type, but something I read in a CPU review on Newegg prompted me to post this question to all of you. I'm interested in buying an Athlon 64 X2 4800 CPU, Brisbane core, socket AM2. If you look at the review from 'Phill' dated 7/2/07 and read his 'Other Thoughts' you'll see why I'm asking:

http://www.newegg.com/Product/ProductRevie...N82E16819103778

He states: "The Brisbane is the 65 watt version of the 4800+ which runs at 2.5Ghz, the previous two 4800+, the Toledo and Windsor, run at 2.4Ghz and are at a tad slower and use a higher wattage. This processor has a greater watt-to-speed ratio giving you the best performance for your money. This processor is not on Tom’s Hardware, they only show the two slower versions of the 4800+. Make sure your motherboard supports the 65nm, 65watt Brisbane AM2 processor. I am using the Abit AM52 with no problem."

I know many of the Newegg reviews should be taken with a grain of salt, but in this specific case I'm not informed enough to know what's true and what's not so I need some help from those of you who know this stuff much better than I do.

Do I need to be concerned about which specific AM2 motherboard I choose to go with this CPU? Or by 'support' does he mean just make sure the mobo has an updated BIOS that'll recognize the CPU?

[ripken204]

dude the guys is an id***. the processor just runs at a lower wattage meaning that it uses less power and creates less heat. that's all.

your are completely right about the socket being what matters. that is a great cpu to get and it overclocks very well. go for it!

[nmX.Memnoch]

Actually he's not an id*** at all. Often times when a die shrink is done the CPU requires less voltage...and often times pre-existing motherboards cannot support the lower voltage requirement. Sure, this isn't always the case but it's something you definitely should research before just purchasing a new CPU and plopping it on your motherboard.

Take the Tualatin version of the PIII as an example. When it was released the i815 based boards that were already on the market wouldn't support them because of voltage differences. You had to either get a new motherboard or an adapter from a company such as PowerLeap.

[ripken204]

Q: Does 65nm require any significant new motherboard designs?

A: Because the 65nm desktop processors are based on socket AM2, there are should not be any motherboard design changes for socket AM2 motherboards, which helps ensure OEM and system builders have a stable platform. Socket AM2 is designed to allow consolidation to help streamline the work for motherboard manufacturers, while helping reduce prices through economies of scale, which can result in better products at lower costs.

http://www.amd.com/us-en/Processors/Produc...5E14633,00.html

according to amd there should not be a need to get a new AM2 motherboard in order to support this processor. that is the way that AM2 was designed..

and comparing an amd cpu now to an intel cpu 8 years ago is a very different thing, they have both changed so much since then.

Edited July 6, 2007 by ripken204

[puntoMX]

Do I need to be concerned about which specific AM2 motherboard I choose to go with this CPU? Or by 'support' does he mean just make sure the mobo has an updated BIOS that'll recognize the CPU?

The CPU you choose is one of my favorites at this moments. It works on every AM2 motherboard as far as I know. And you are right, the BIOS needs to be updated sometimes to see the right model, some motherboard will give you a message like "Unknown CPU detected working on X.XGHz".

@ nmX.Memnoch,

Take the Tualatin version of the PIII as an example. When it was released the i815 based boards that were already on the market wouldn't support them because of voltage differences. You had to either get a new motherboard or an adapter from a company such as PowerLeap.

Voltage wasn´t the problem there, it was the pin lay-out that wasn´t 100% (g37 and g35 needed to be bridged) compatible altrough it was Socket370. Sure you normaly needed to lower the voltage but without doing it you could OC a bit more . Those babys ran faster then the first PIV .

@ ripken, you´r right, the man is scaring people with his post...

[Alpaca Portrait]

Thanks for the quick replies. I kinda thought he was talking smack, but I thought there might have been some truth to it. Maybe if he had worded his statements a little better.

The CPU you choose is one of my favorites at this moments. It works on every AM2 motherboard as far as I know.

I did a little research and it seems like that CPU is the current "best bang for the buck" model. To jump from the 4800 to the 5000 is an extra $50 and doesn't seem worth it.

Mr. Punto, aren't you in the PC business in some capacity? Could you recommend some AM2 motherboards I could take a look at? I'm just interested in a stable system, not really interested in hardcore gaming or overclocking. I know I'll need DDR2 memory. I'd like a gig to start with (512x2). DDR2 prices have dropped a lot since I last looked at memory prices 6 months ago. I don't know much about DDR2.... doesn't it have higher latency than 'regular' DDR but it makes up for it with higher bus speeds? The DDR in my current PC has 2,2,5,2 timing.

If you could make some mobo and DDR2 recommendations I think I could do the rest.

[nmX.Memnoch]

and comparing an amd cpu now to an intel cpu 8 years ago is a very different thing, they have both changed so much since then.

The same information still applies. It's the same reason you couldn't run Prescott P4's on pre-existing motherboards, even though the supporting chipset was still the same. The VRM's had to be updated to correctly support the new voltage requirements. It happens when they address design limitations on new steppings/cores of a given CPU family. AMD has done it before as well...they just usually opt for changing the entire socket when it happens.

@ nmX.Memnoch,

Take the Tualatin version of the PIII as an example. When it was released the i815 based boards that were already on the market wouldn't support them because of voltage differences. You had to either get a new motherboard or an adapter from a company such as PowerLeap.

Voltage wasn´t the problem there, it was the pin lay-out that wasn´t 100% (g37 and g35 needed to be bridged) compatible altrough it was Socket370. Sure you normaly needed to lower the voltage but without doing it you could OC a bit more . Those babys ran faster then the first PIV .

Voltage was most definitely the 'problem'. Do some research on the different VRM specifications between the Coppermine and Tualatin PIII's. The voltage change was the reason for the pin layout change. It was changed so that you couldn't physically install the CPU on a motherboard that didn't support it, thus potentially resulting in a brand-new fried CPU.

[ripken204]

Alpaca-how much do you plan on spending for a mobo?

Edited July 6, 2007 by ripken204

[puntoMX]

nmX.Memnoch

Do some research on the different VRM specifications between the Coppermine and Tualatin PIII's.

Did you ever tried it on that voltage? Never fried any CPU here, not even a Celly 600@2.2volts for months...

Do your research again .

Alpaca Portrait

You are going to order it from a online shop? If so tell me where so I can give you my 2 cents..

[Alpaca Portrait]

You are going to order it from a online shop? If so tell me where so I can give you my 2 cents..

Yes, I'll most likely be ordering from Newegg. I think I've ordered all my PC stuff there except one time.

[puntoMX]

Okay, tell me:

- Pricerange

- Onboard devices

- Connectivety

It could also help if you tell us where you use it for...

[Alpaca Portrait]

Price range: Hopefully under $110. I just checked Newegg and it looks like most are under $125

Onboard: 2-channel sound. I don't use any standard PCI devices. I'll get a separate low-end PCIe video card (I don't really game much). Don't care about RAID, firewire, infrared, all that stuff.

Connectivity: Not sure what you mean exactly, but my HDDs are all SATA. If I get a board without any PATA connectors can I use an IDE-to-SATA adapter for my DVD? LAN for my DSL. Whatever USB it comes with is fine.

It's just going to be a basic computer used for internet/e-mail/newgroups. It'll also have about 200GB of music on it. I'll be doing music editing, and short (less than 15 minute) video editing of videos I put on Youtube.

Ideally I'd like to put it in the smallest case possible, like one of those LANboy/gamecube ones or whatever they're called, but if that's going to severely limit my motherboard choices then I'll just go with an unused mid-tower I already have.

[puntoMX]

Good, got the point.

As far as I can see you can use onboard VGA. So I thought about a ASUS M2A-VM HDMI Socket AM2 AMD 690G motherboard. As you can see it even has DVI and HDMI.

Looks like onboard sound will be okay to start with, all are 6 or 8 channels now. There are 2 PCI slots that you can use for an add-on soundcard if you don´t like the onboard one.

It has PATA connector so you can still use your "old" optical drives as well .

It also has onboard LAN 10/100/1000Mbps and FireWire, so you can connect you, if DV or so, camera directly to it.

EDIT: The Case: COOLER MASTER Centurion 541 RC-541-SKN1 Black Just take a look at that one, it comes without a PSU so you make your own choice on that. This case is small but well made. A lot smaller then the Antec Lanboy for example. The only bad thing is that some versions have a FireWire connector in frond and some don´t.

The RAM: 2 of A-DATA Value Series 1GB 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) would do fine. Selling them to here, people are pleased with them and there are almost no returns (1 out of 130 in 1 year). If you don´t know the brand you can take a look at the Kingston 1GB 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400). I would buy 2 of 1GB, now there are still cheap but prices are going up again.

Edited July 6, 2007 by puntoMX

[Alpaca Portrait]

Thanks for the help. As far as the case goes, when I said 'small' I meant something more like a cube with a handle on top, but I know those tiny cases have to use smaller mobos, so if that restricts my choices too much I'll just stick with the case I already have. Ideally what I'd like ot be able to do is pick up the case in one hand and the LCD in the other and walk to another room and plug in (and no, I don't want a laptop).

You mentioned using onboard video. I've never done that, so I have some questions:

1. Doesn't it automatically use your system memory?

2. How do you control how much it uses?

3. If you decide at some point to get a video card, do you just disable the onboard video in the BIOS like anything else you don't use?

I also have another question about RAM. I saw this posted elsewhere but never saw an answer to it:

Every mobo is built to run best with just ONE size and shape and chip density of RAM.

Deviate from that perfect match of mobo and RAM and you've got a problem.

How do you find out what chip density a particular mobo is designed to work with? Those kinds of details seem like the kind of thing that would be left out of most mobo specs. So how do you know or find out?

[ripken204]

1. depends on the mobo, you need to check if it's shared or dedicated video memory

2. in the BIOS

3. yes

by density i think he means the size of the memory, such that many motherboards cannot use sticks larger than 2gb of ram per slot.

Edited July 7, 2007 by ripken204