mATX vs ATX

[Spudwell06]

I'm looking at different budget AM4 motherboards, and they all seem to be mATX

Is mATX bad/outdated/not future-proof

Mainly, is mATX big enough and have room to expand 

[Haro]

2 minutes ago, Spudwell06 said:

bad/outdated/not future-proof

What?

 

2 minutes ago, Spudwell06 said:

Mainly, is mATX big enough and have room to expand 

I mean it's not itx. There's some room for that. 

What cpu are you powering?

Budget? 

[Moonzy]

"it's not the size that matters, it's how you use it"

 

if all you plan on plugging in is a GPU, even an mITX board will be fine

it depends on your personal needs

[WereCatf]

10 minutes ago, Moonzy said:

if all you plan on plugging in is a GPU, even an mITX board will be fine

it depends on your personal needs

Precisely this. I, personally, always insist on buying ATX instead of anything smaller, because I know I will repurpose the PC as a server when I, one day in the future, decide to upgrade my desktop to new hardware, and ATX-mobos have much more expandability than e.g. mATX. If I only wanted a desktop and wasn't going to repurpose the PC as a server later on, I could just as well make do with mATX, since I just don't have that much need for expandability there.

[infigo]

Expandability on ATX boards is not as good as you think compared to mATX boards 

On b550 which I have done most research on you have 24 lanes total 16x gen 4 to GPU, 4x lanes to gen 4 m.2 nvme ssd. 

Then all boards in some way have squized in a single 1x lane to the cpu which is used for wifi card or just as a 1x slot.

There are 8 gen 3 lanes from the chipser which I do believe share a 4 lane gen 3 bandwidth from the cpu to the chipset 

But for motherboards using a m.2 that is 4 lanes taken (in most cases, asrock only use their chipset connected m.2 with 2 lanes) 

Then you have a maximum of 4 lanes to other ports.

On a Asus ATX board that is either a 4x slot or 4 1x slots, but on their mATX it straight up a 4x but the WiFi version takes that down to a 2x IF a 1x lane is used (non WiFi version the 1x is cpu and not chipset)

MSI just disable the chipset m.2 ssd if a card is placed in the  second 16x slot (4x electrical)

Asrock have enough bandwidth since they only use their chipset ssd with 2 lanes.Yiu will have more option with component spacing on a ATX board but you can basically have the same expansion with a mATX board as you will be lane limited and on the mercy of the actual implementation. 

For example MSI b550 A-pro ATX board looks good right? Well if you use a graphics card wider than 2 slots you overlap the first 1x slot, only a 16x (4 lanes connected) and a 1x slot. If the 16x is used you get No second m.2 so you only have a 1x slot expantion in ATX board.

Asus b550m tuf gaming you can use a 1x card in the top 1x and an m.2 and if you only have a 2 wide slot graphics card you can use the bottom 16 slot (2 lanes on WiFi model if 1x is filled and 4 lanes in non WiFi model) without disabling the m.2. 

So it is not just black and white but for most people there could be a mATX for them as ATX give nothing more than spacing between slots. some boards like MSI repurpose 1 or 2 lanes to usb c 10 gigabit front panel which steals lanes to be used as expantion. 

Z490 is similar lanes wise to b550 but always look in the manual for limitations in either expantion slots or storage as they have asterisks there on how you can use them.

On x570 and HEDT platforms you have more lanes and then an ATX board will have more expandability but if you need that then you don't need to ask this question.

I like ASUS the best in this regard as they use a 4x m.2 and a 4x slot (or up to four 1x) while others either skimp on m.2 lanes or disable the second m.2 all together