Time to finalize this build log...
After playing for days with Sapphire Pulse RX570 ITX VBIOS modding, I've got to the the point of what I think is an optimal balance between card power usage and performance under thermal conditions for this build. I've set the max VBIOS power to 85W, but also had it under-volted to its limits, as well as under-clocked in higher power states. I had to learn how to adjust power states voltages, down-clock hem, even adding proper VDDC voltage offset registers to the VBIOS from scratch, not to mention adding special UEFI GOP. An interesting learning experience, indeed, if one don't mind the risk of bricking a brand new and by no means cheap graphics card...
I did expect to go through this kind of hassle when I decided to go with Sapphire R750 ITX, but for those that may to build similar system without any such worries, properly sized RX560 or even GTX1050 might be much better choice. Same can be said for CPU, perhaps a Ryzen 1600 would never even reach the throttling point in this setup?
That said, here are some final touches I did to my black obelisk build... One final metal mod had to be done to officialize the friendship between Stracom chassis and HDPlex PSU. Two small holes were needed on the power lid plate provided in the chassis set so that Strecom and HDPlex can stick happily together for the rest of the lifetime of this box.
The lid plate fitted nicely, as can be seen from below.
Finally, I added a pair of Plextor SSDs, both tightened to a single DB6 metal bracket.
Because the aluminium heat blocks are now firmly attached to all four sides of a main chassis body, there is little room left for hard drives, which is exactly the reason I'm using single bracket for two drives. But with careful placement, there is just enough space left for one more such pair if needed. In that sense DB4 is really remarkable, even in this hybrid and highly cramped setup I could have had added total 5 storage devices (1x M.2 below the MB & 4x 2.5 inch SSDs) if I really wanted to.
That is it, after all pieces put together, this is what the final "product" looks like...
And how does this thing run? I've just played Witcher 3 for about 3 hours, with all graphics settings maxed out @ 1920x1080, it runs very smooth... Under that kind of load the GPU temp never went over 74C, and the CPU never above 70C. These longer running loads makes the chassis dissipate the heat nicely an evenly across the surface, although when touching certain parts of the aluminium heat-sinks one can feel as if it almost going to burn your fingertips. The only things that worries me a bit, temperature-wise, are VRM heat-sinks, on both MB & graphics card. Both have just a small passive heat-sinks now, which by no means conduct the heat outside of the chassis. I wonder if there is some relatively simple way to connect them to the chassis with at least a sole heat-pipe... Suggestions are more than welcome!
During this quiet night Witcher 3 session, especially when rendering some graphics intensive scenes, there was this barely audible fan noise coming from the case... ?!? Wait, what fan noise? Yep, it was definitely a noise, not coming from some non-existing ghost fan, but from Sapphire RX570 ITX VRM coils. Surprisingly, the coil whine on that thing is really obvious, especially on a quiet night with minimum ambient noise. It is also inconsistent, so it is worse when the card is under heavy load, and it sometimes sings in somewhat annoying synth-punk-like patterns. I bet it could be heard even if that stock GPU fan was on (BTW, a stock fan WAS pretty quiet when I tried it, even under load). The coil whine got little less obvious when I further under-volted the card, but I still have to learn how to live with it. Luckily, there are absolutely no audible coil whine coming from motherboard or PSU or GPU when graphics is idle, no matter how high the CPU load is. Biostar B350GTN MB and HDPlex DC PSU are quiet as they can be, it is only the Sapphire that becomes somewhat noisy under graphics intensive loads, benchmarks especially.
In Linux I have still to run workloads that would bring the temperatures significantly up, under standard desktop activities the chassis was uncompromisingly nice & cool & quiet, like I always wanted these things to be
Overall subjective impression; I'm happy with this black box, hope it would serve me for years to come.
