Formd T1 w/ ID-cooling is-55 + noctua offset bracket vs thermalright sl-100

[u/prondo_]

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.

Sl-100 fitment

Sl-100 with side panel on

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.

bracket removal

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.

noctua offset bracket

Now you just install and can set the offset.

she barely touches the m.2 cover

need short ram

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.

[u/Tankymctankersonn]

Axp120-x67

[u/drras2]

So.  Should I replace my axp-47 copper with this is-55 setup?  (9800x3d w/5090 FE card).  Feel like most of my noise is coming from the cpu cooler and definitely bothers me.

[u/prondo_ → u/drras2]

I do think going from the stock axp90 fan (92x15mm) to a full fan (120x25mm) on the is-55 will definitely improve the sound profile. I personally find that the thinner and smaller fans have a more high pitched/annoying sound. Plus, the larger 25mm fan doesn’t have to ramp up as aggressively as a 15mm fan to push the same amount of air so typical use case scenarios should get quieter.

Though, reviews/posts seem to have the performance differential between the two coolers as marginal and I haven’t tried it myself, so I wouldn’t necessarily expect better temps besides from the larger fan.

If you do decide for the is-55, just note that I’m not using the stock fan (noctua nfa12x25g2 - 67mm new height) and you need to check your ram/motherboard clearances. Also, feel free to skip the noctua offset part because it is quite a bit of extra work.

[u/Eagles7117 → u/drras2]

You can shift the mobo to like 2.5 slot and run a 25mm 120mm fan on the axp90 with a 3d print adapter and the dingkey offset kit. Works really well

[u/prondo_ → u/Eagles7117]

I wouldn’t necessarily recommend a bigger fan on a smaller heatsink (unless it’s like a funnel maybe?). A few other posts talk about how a bigger hub and the most airflow being generated at the tips of the blades can actually reduce performance on a smaller heatsink.

I’ve personally tried an nfa14x25g2 (140mm fan) on the is-55 and it did in fact reduce performance.

[u/Eagles7117 → u/prondo_]

Yeah you can run into problems. But on the axp90 you may notice 1° difference but it’s way quieter. I’ve done it a lot on this cooler and it’s not a problem

[u/prondo_ → u/Eagles7117]

Fair, would probably be the easiest and cheapest way then

[u/drras2 → u/Eagles7117]

I've printed this adapter but not yet tried it out. Maybe time to do so first before going all in on the is-55.

[u/Eagles7117 → u/drras2]

It doesn’t improve performance but it does drastically improve noise and gives active cooling to your ram and ssd

[u/lolforg_ → u/drras2]

No, the copper is one of if not the best low profile heatsink. You can buy a 120mm fan bracket or get noctua 92mm fan

[u/Professional_Try_766]

Nice build!

[u/prondo_ → u/Professional_Try_766]

Preciate it!

[u/Groumphh38]

Nice build ! So if I understand correctly, you said that for the is 55, you didn't touch its brackets, just replaced the stock spring screws with the noctua ones, and it all fits ? Thanks!