I have been experimenting a little with undervolting and overclocking the GPU by using a software called LACT.

To install LACT, go into desktop mode. Search for the flatpack LACT and install it. Open the software. Enable overclocking inside the app (it will give you an error). Close the error and close the app. Then reboot. Upon reboot, go into desktop mode and open LACT again. You can now use the overclocking settings for the GPU.

I have set mine to -100mV on the core (undervolt) and +100Mhz for the core (overclock).
Then I played some 4k Tomb Raider GOTY, and also ran some 3Dmark stresstests. I ran Steel nomad and Fire Strike ultra stresstests and both came back with a pass at 99.7% accuracy.

I have also tried to overclock the memory with +50mhz (to 2300 instead of 2250), but that did not seem to be stable and came back with an error in God of War rather quickly.

Running a 3Dmark firestrike results in a small uplift in performance. Which is in line with the increased coreclock speed (4%, 100mhz).

What I can also say from my testing is to not enable "Game Recording" as it is an absolutely performance killer. So only activate it if you really need it.

So the standard network interface on the Steam machine is a 1 Gbit link. Let's face it, we can consider this network speed to be "legacy", as most people are in the process of upgrading or have already upgraded their backbones to 2.5Gbit and beyond. Many motherboards do already come with an integrated 2.5Gbit (or even faster) for their networking needs.

With the option to transfer your gamefiles from another computer baked into the Steam Client, we want to have our games installed without too much waiting. With a 1Gbit link you will be waiting 2.5 times longer. For a game like Baldur's gate which is 100+ GB, it is a LONG wait.
For people downloading/running/storing their games on a NAS, this upgrade will also be important to you.

The solution is to replace the internal 1Gbit network port by an external USB 3 adapter. Preferably one that has a Realtek RTL8156 or RTL8156B chipset. Since I had a spare Cable Matters USB A/C 2.5Gbit 202025 which has a RTL8156B chipset lying around, I decided to use that one.

Power down the steam machine. Attach it to the 1 USB C port in the back. Powering down during this process is important because otherwise after every reboot the USB connection will reset itself to 480Mbit speeds. A weird quirk that I was able to figure out after some testing/troubleshooting.
Steam OS recognizes the device and uses the realtek r8152 driver.

Go into desktop mode and check Info center. Make sure the USB device runs at 5000M speed (and not 480M). Doubleclick the network icon in the taskbar and check if the network speed is now showing 2.5Gbit.

If you want to use SSH command line (either local or remote) to check if everything is OK:

lsusb -t
(should show a line saying // Port 001: Dev 002, If 0, Class=Vendor Specific Class, Driver=r8152, 5000M //

nmcli device status
(to check for the device name of the new network dongle, for me it is enp9s0f4u1)

nmcli -f CAPABILITIES.SPEED dev show enp9s0f4u1
(should show 2500Mb/s)

Happy gaming!

I have tested the microsd card reader of the Steam machine with 2 different cards to determine which card I should use to run my emulators off.

card 1
512GB Samsung Sonic Pro Plus U3 V30 A2 Microsd

card 2
1TB Silicon Power U3 V30 A1 Microsd

card 1

               KDiskMark (3.2.0)

[Read]
Sequential   1 MiB (Q=  8, T= 1):   160.332 MB/s [    156.6 IOPS] < 44504.73 us>
Sequential   1 MiB (Q=  1, T= 1):   156.503 MB/s [    152.8 IOPS] <  6427.19 us>
    Random   4 KiB (Q= 32, T= 1):    24.253 MB/s [   6063.4 IOPS] <  5106.93 us>
    Random   4 KiB (Q=  1, T= 1):    22.994 MB/s [   5748.7 IOPS] <   167.62 us>

[Write]
Sequential   1 MiB (Q=  8, T= 1):   136.925 MB/s [    133.7 IOPS] < 52039.17 us>
Sequential   1 MiB (Q=  1, T= 1):   130.777 MB/s [    127.7 IOPS] <  7492.62 us>
    Random   4 KiB (Q= 32, T= 1):    13.274 MB/s [   3318.5 IOPS] <  9330.22 us>
    Random   4 KiB (Q=  1, T= 1):    15.378 MB/s [   3844.6 IOPS] <

card 2

               KDiskMark (3.2.0)

[Read]
Sequential   1 MiB (Q=  8, T= 1):   157.953 MB/s [    154.3 IOPS] < 44937.40 us>
Sequential   1 MiB (Q=  1, T= 1):   155.009 MB/s [    151.4 IOPS] <  6489.67 us>
    Random   4 KiB (Q= 32, T= 1):    16.375 MB/s [   4094.0 IOPS] <  7562.06 us>
    Random   4 KiB (Q=  1, T= 1):    15.809 MB/s [   3952.5 IOPS] <   246.78 us>

[Write]
Sequential   1 MiB (Q=  8, T= 1):   145.855 MB/s [    142.4 IOPS] < 48628.64 us>
Sequential   1 MiB (Q=  1, T= 1):   136.229 MB/s [    133.0 IOPS] <  7221.58 us>
    Random   4 KiB (Q= 32, T= 1):     7.349 MB/s [   1837.4 IOPS] < 16827.15 us>
    Random   4 KiB (Q=  1, T= 1):     7.387 MB/s [   1846.9 IOPS] <   532.51 us> 

Looks like sequential read speeds of the cardreader max out at around 160MB/s for me.

I realize both cards are UHS-I cards. And while I do not have any UHS-II or UHS-III cards to my disposal, I believe this will be the max speed for this integrated card reader.

What I can say is that in the end I choose the "Sonic" card to use as the main card for retrodeck. And in my testing, speeds of emulators (even demanding ones like RPCS3 and Xemu) are working just fine. Not blazing fast like an nvme but not causing stutters or slowdowns either.

For the people who still have some OG Steam Gift Cards laying around: The height of these cards fit the front of the machine perfectly. Just stick it on using some double sided tape and you are good to go :) Brings some color to the front.

Steam stopped producing these physical gift cards recently so not sure if you can still buy them anywhere.

What way did you guys come up with to quickly/cheaply customize yours?

What I have noticed is that sometimes after resuming from sleep, the cpu speed only knows 2 speeds: 544mhz and 1091mhz. It gets mostly stuck in 544 making the interface sluggish. when booting a game it "boosts" to 1091, but of course that makes everything unplayable.

My take is that this has something to do with the nightly scheduled updates that I have set. My schedule for game updates is to do it at night. It does it in a sort of sleep state I think and does not properly recover from that state after waking up.

A reboot brings back full speed.

Anyone else having this issue with a possible explanation as to why this is happening?

I am on the beta channel. My software versions are: OS Build 20260716.2 , kernel 6.16.12
BIOS F7F0106
Steam version 1785347151

Upgraded the Steam Machine to 2x16GB right when I got it. Just so I do not have to think about it anymore in the next few years. It was not for the 32GB per se but more so that dual channel gets enabled.

If any of you are contemplating about upgrading but want to compare benchmarks with your single stick: let me know what benchmark you would like me to run for you to compare against.

The process of putting the second sodimm stick in is not very easy I have to say. Keep that in mind. Upgrading the m.2 storage is wayy easier.