From the looks of it there are three different sets of holes for different fans on this case.
Compatible sizes are either 80mm, 92mm and 120mm or 92mm, 120mm and 140mm.
Based on that a 92mm and a 120mm fan should be a safe bet. I would opt for the larger fan spinning at lower RPM.

How do you measure?
From screw hole to screw hole ?

What fan do you recommend.
Inexpensive but reliable.

NO RGB Please.

no, fan size is defined by frame width

120mm fans have a hole spacing of 105mm
140mm fans have a hole spacing of 124.5mm
center to center

judging by the picture it has holes for 80, 92 and 120mm fans (ATX I/O is cutout 159mm so a 140mm one would be larger in relation to that)

Intel486dx33 wrote on 2020-09-21, 20:32:

How do you measure? From screw hole to screw hole ? […]
Show full quote

How do you measure?
From screw hole to screw hole ?

What fan do you recommend.
Inexpensive but reliable.

NO RGB Please.

Noctua is the only brand worth mentioning here.

Intel486dx33 wrote on 2020-09-21, 20:32:

What fan do you recommend.
Inexpensive but reliable.

NO RGB Please.

Arctic fans are actually decent and have a very good price (even if not as popular).

To my knowledge fans are measured by their outline. 120mm means the fan frame measures 120mm*120mm. Thickness differs but 25mm is the most common.
I think Arctic has some fans with good price-performance ratio. But I don't really know enough about fans to recommend one. Sorry.

An AT board in an ATX case? What is this madness?

Well I'll be the rebel and say I love Corsair's airflow AF120/140 series.

Correct, the fan size is measured in mm, across two sides (edges) not the mounting holes as I have obsession with fans.

Cheers,

Errius wrote on 2020-09-21, 23:28:

An AT board in an ATX case? What is this madness?

A baby AT board with ATX power connector too... it reminds me of the FIC 503+ but I can't quite place it.

As for the case, whoever designed it actually did a great job for flexibility. It looks like they have holes for 80mm, 92mm, even 120mm.

That said, no matter what size you put in there, it's going to be pretty worthless because the vent holes stamped in the case metal are just too small. A 4 1/2 inch hole saw (114mm) (or dremel) and a 120mm fan grill will be *required* to flow anything through that.

THAT SAID do you really need a fan there? Baby AT doesn't really hot-spot at the "top" of the board and even just the ATX power supply exhaust should suffice to vent that area.

I seem to remember on AT layouts whatever is the lowest FRONT intake on the case is more a priority since processors and VRMs like to live there.

And what's nice about that is if you don't want to spend out for that 4 1/2in hole saw + a drill to cut it... the front panel hides all the ugly dremel butchering to fit a 120mm fan down in front =)

Yet... again (I'm such a joykill) ... unless you're going to run a peltier kit (Hey, it's historically correct https://www.overclockers.com/swiftech-mc370-2 … ltier-heatsink/ ) any good 370 / socket A heatsink using clip attach will probably provide overkill cooling to max most socket 5/7 chips running ambient. Short of building your own phase-change or finding an kyrotech ;p

I guess this is my super round-about way of saying that... you probably don't need a fan for a baby-AT system in this case.

I ended out swapping the motherboard out for a full size ATX Intel 370. ( Asus CUSL2 )
The case has good ventilation with both side panels perforated.

So I can blow air in or out which is best with this case ?

I only have the one rear fan to add.

Intel486dx33 wrote on 2020-09-22, 01:38:

The case has good ventilation with both side panels perforated.

With both side panels perforated, combined with the fact that a socket 370 system isn't going to get that hot w/o some crazy volt-mods - it just doesn't matter.

The case you have is like crazy future alien technology compared to the fully enclosed beige cases back in the day.

Your case already has more ventilation than anything they could have hoped for back in the day, and 370 systems don't run hot enough generally to heat soak a case anyway.

You'd probably be better off to remove the chipset heatsink, scrape off the "bubble gum" TIM, and then use actual thermal paste and reattach the chipset sink.

xrror wrote on 2020-09-22, 00:49:

That said, no matter what size you put in there, it's going to be pretty worthless because the vent holes stamped in the case metal are just too small. A 4 1/2 inch hole saw (114mm) (or dremel) and a 120mm fan grill will be *required* to flow anything through that.

While I would of course agree that smaller holes do obstruct airflow more than bigger ones I wouldn't go as far as to say there's no airflow possible through that fan grill. Especially with a nice static pressure optimised fan you'll be able to pull heated air from the CPU area out of the case.
Wether this is necessary with this very open case design is another question. 😉

kolderman wrote on 2020-09-21, 23:38:

Well I'll be the rebel and say I love Corsair's airflow AF120/140 series.

I was disappointed with their build quality compared with Aerocool Dead Silence in another build. Both do a decent job of pushing air round though.