There are two Common Form Factors of motherboard when you go to build a Computer. One is called ATX, and another one is Micro ATX. The Major Difference between these two is More cleared from their name as well that Micro ATX is smaller in size than ATX Case. The size of the ATX Motherboard is almost 305×244 mm, while the Micro ATX size is 244×244.
One More Big Difference between these two form factors are expansion slots. Expansion Slots of Micro ATX Motherboard are less than the ATX Motherboards. Where ATX have five PCIe slots. MicroATX has three places and a maximum of 4 slots in some exceptional cases.
Because Micro ATX is smaller in size than ATX, that’s why Micro ATX can be fitted into ATX. But ATX cannot be fit into the Micro ATX Case.
Another big difference between these two is the number of drive bays. Micro ATX chassis has fewer drive bays than the ATX.
Here are the Main Factors on which basis you have to decide which one is best for you as per your needs.
Related: https://techmotherboard.com/atx-vs-micro-atx-vs-mini-itx/
PCIe Slots
When You want more PCIe Slots, then you will definitely go with ATX.because ATX has more PCIe Slots than the others.ATX has a minimum of 3 PCIe slots and goes maximum to 5 slots as well. On the other hand, Micro Atx has one space and goes up to 3 PCIe slots.
PCIe slots are more essential for you to in the only case when you will install Multi GPU setup or when you will think about installing other extra cards like a sound card etc.
RAM Capacity
Both ATX AND Micro ATX motherboards usually come with 4 Ram slots. But ATX can also go up to 8 places in some case.RAM capacity is not a big issue between these two because four ram slots are more than enough for budget gamers. But when you are going for a high-end PC and need more RAM capacity, than the ATX motherboard is the best option.
Price
When you go to Price Comparison for both ATX and Micro ATX Motherboard, you will see ATX Motherboards Costly than the Micro ATX Motherboards.
The high price of ATX motherboards is just due to Bigger than others, Higher numbers of PCIe slots, More Space for Drives, and Ram capacity is More than the Micro ATX motherboards.
Multi GPU Setup
When you think for Multi GPU setup, you will obviously have no choice other than ATX motherboards. Because Micro ATX can support only one GPU.the newest models of Micro ATX Motherboards has the capability of two GPUs as well, but the price of these Micro ATX motherboards is almost equal to ATX.
Which form Factor you Should Choose?
It depends upon your requirements that which type of Form Factor you will choose. We will advise you that when you don’t need more PCIe slots and Mainly you will use for Gaming purpose, go with Micro ATX motherboard because it is cheaper than the ATX. Typically for Gamers, Ram capacity and PCIe slots of Micro ATX motherboards are more than enough.
On the other hand, when you will use your PC for gaming as well as for Professional work like High Graphics Softwares like Android Studio, Adobe After Effects, and another one than Micro ATX, motherboards will not be a right choice because high graphics work will need More cooling .and when you go for More Coolers than you definitely need more PCIe slots, so in that case, you have to choose ATX always.
The most significant advantage of Micro ATX Motherboard is that it can be fitted in any case with almost all features. U can check here for more technology information.
Final Verdict
When budget is not an issue for you and wants to build a very High-end PC with Multi GPU setup, more PCIe slots requirements, and more than 4 Ram slots needed, then go for ATX motherboards.
When you have to consider the budget and just single GPU work with not so much PCIe slots Required, than go with Micro ATX motherboards.