Formd T1 w/ ID-cooling is-55 + noctua offset bracket vs thermalright sl-100
Decided to do a little testing with the intention of min-maxing CPU cooling in 2 slot mode (73mm). These tests are by no means scientific, but may be useful if you're looking into either of these coolers. Tldr at the bottom.
The testing was done with a 9800x3d with a -20co undervolt (I have a per core co set up but it averages to around -20) and noctua nf-a12x25 g2 + nf-a12x15. These are synthetic all core workloads so you can expect significantly lower temps while gaming or during non-workstation use.
Also, the is-55 (stock) and sl-100 (15mm fan on bottom) required low profile ram. My ram height is ~33mm and both configs look like they can fit a couple more mm.
SL-100 fitment:
First of all, without the fan, the sl-100 comes out to 75mm in height (2mm too high). However, with the panel on, there is minimal if any flex.
In order to fit a 15mm fan under the sl-100, you have to remove the small bracket under the cooler. I used some long pliers to undo the screw and then the bracket just slides out.
SL-100 results:
- 15mm fan (under) pulling air through rad towards motherboard
- Hits tjmax of 95°c in ~10 seconds dropping to 5ghz
- 15mm fan (under) pulling air from motherboard pushing through rad
- Hits tjmax of 95°c in ~60 seconds dropping to 5.1ghz
- Adding a 25mm fan on top in either orientation doesn't seem to help temps/boost at all
- Only 25mm fan (top) pushing through rad towards motherboard
- Stable 85°c maintaining max boost of 5.225ghz
In my testing, it seems like adding a 15mm fan under the SL-100 with a 25mm on top (for both orientations) actively hurts cooling performance with the cpu hitting 95°c. While, with only the 25mm fan on top, it's able to perform as expected.
Since the sl-100 can only fit with the 15mm under, I don't think its worth the effort as it doesn't perform any better than would a smaller, properly fitted, cpu cooler.
IS-55 + noctua offset fitment:
Here, I used the noctua NM-M1-MP83 offset bracket.
noctua brackets are the wide ones
The noctua cpu cooler brackets screw holes don't line up, but you can undo the is-55 brackets and switch over the tightening spring screws to the is-55 bracket. I personally just broke off the is-55 metal retainer things and for the noctuas, there's an opening so you can just slide them off and on.
Now you just install and can set the offset.
she barely touches the m.2 cover
is-55 + 25mm fan leaves enough mm of clearance where there is no audible turbulence against the side panel. Also, the is-55 does not come with screws for a 25mm fan. MAKE SURE to get the correct length otherwise you'll screw straight into the rad.
IS-55 results:
- 25mm fan w/o offset
- Hits 95°c in ~60 seconds dropping to 5.1ghz
- 15mm fan w/o offset
- Hits 95°c in ~10 seconds dropping to 4.9ghz
- 25mm fan w/ offset
- Hits 95°c in ~5mins maintaining max boost of 5.225 forwards
- 15mm fan w/ offset
- Hits 95°c in ~20 second sitting at 5.1ghz
The offset does seem to add a good bit of performance. It's the only way I can maintain max boost during a synthetic all core workload.
Tldr:
Sl-100 can only fit with 15mm fan under. It performs poorly don't do it. Also, don't put a 25mm on top and a 15mm under, it reduces performance significantly. Is-55 with noctua offset bracket performs better, w/ it maintains max boost w/o it drops to 5.1ghz. Also, I find the 25mm fan sound profile much more pleasing at max rpm vs the 15mm.
Hope this is useful for some people, I tried to make it as in depth as possible for fellow lurkers like me who like to tinker based on other peoples posts.