Unlike the review posted here, I have actually got a couple of new T655s cheap because they had suffered slight case damage, and I examined and benchmarked them. It was a disappointment.
What you get quite a lot faster processor than a T640, faster RAM at DDR4-3200 and faster graphics. But HP has cripped the SSD. It has reduced it from the gen3x4 in the T640 to gen3x2 in the T655. That halves the hard drive access speed. So its still faster than a SATA SSD, but not by much.
The SoC does not impose this limitation. It has a full gen3x4 interface. HP has chosen to only implement two lanes to the M.2 socket.
Manufacturers of IT equipment should be designing them so that instead of getting thrown out as ewaste hobbyists or others want to buy them and repurpose them. Instead HP has chosen to make this product less attractive.
First of all - this is not a review of one, it’s really a resource summarizing what’s the benefits and drawbacks of having one.
I did specifically mention on the resource that I do not have a t655, and on a non-related discussion mentioned that I don’t think they are a good value, whether at retail pricing for one at the time I wrote it back in Q1 2024, especially if you already have a t640,
or more recently in Q3 2025. I still don’t think they are a good value now at Q4 2025 at secondary market pricing (eBay asks at least 150 for one) while both t640s and t740s can be had for between 50-100, or a t540 at ~35.
Why do I think the t655 is not a good value at 150? It’s just a t640 but with 4 cores (instead of 2). Going from 14nm to 12nm (which makes it a Picasso/Raven2 APU instead of a Raven Ridge/ Raven1) might net you a slight performance increase per core (maybe 5-8%?) but the real gain is from the 2 extra cores, 3 extra GPU Compute Units and thermal headroom to clock them higher - but even then it's maybe about 50% faster (not 100% faster). The R2314 is a long availability Ryzen 3 3350U notebook APU, and it is housed in a passively cooled enclosure. It also doesn’t do DDR4 at 3200MT...It’s capped at 2666, so at the most you are looking at is (maybe) 10% more memory bandwidth.
If I want a quad core Raven2 (and that's a very big "if" - it's Zen1 based and I would prefer at least Zen2 or Zen3), I would've gunned for a ThinkCentre 715q Gen 2 with a Ryzen 3 2300GE. Roughly the same horsepower and available at 80-100 - for 150 there are off-lease Lenovo m75q-1 with Renoir/Cezanne APUs that will provide better value for the money - in fact,
someone is selling them barebones for about 60 or BO at the end of 2025. If you want something around the same price point I would've gone with one of those 80 dollar
Seneca Element Tiger Lake i3s - weaker CPU but newer iGPU, and housed in a metal chassis for better thermal management. Those have 8/10 bit AV1 decoding built into Quicksync. AMD's VCN counterpart doesn't even offer AV1 decoding until VCN3.1 on the Zen3 based Rembrandt APUs.
As for the NVMe lane halving? The t640/655/740/755 design use a Sandisk Mothim NVMe eMMC card as their primary storage (same tech level as the SD7Express card on a
Nintendo Switch2), which use one PCIe 3x1 lane, and I don't think most ship with a full fat NVMe drive included as both HP ThinPro and Windows embedded LTSC implement copy-on-write to preserve flash write cycles. Even If it did, no one expect them to be high throughput speed demons - its still sitting in the same plastic enclosure being passively cooled as the APU and that Picasso APU isn't exactly breaking speed records back in 2019 when it was new, and the NVMe drive is likely just as expensive, if not more so than the APU itself. Yeah, it sucks that the lanes are gimped especially when compared to its nearest Lenovo equivalent the
m75n thin client - that one is running full PCIe 3x4, even when it only has 8GB of RAM soldered. If you want to see an example of eWaste, that m75n is even more of an instant eWaste product than the t655. The same goes for the Igel UD3 - same as the t640 but with soldered eMMC.
Well, actually, how much of a dealbreaker is it in a 1 NVMe slot homelab machine? Let's see how's my theoretically much faster, Zen2 based t755 is doing...
Code:
root@proxmox01:~# dmidecode -t 1 | grep Name
Product Name: HP Elite t755 Thin Client
root@proxmox01:~# lspci -vvv | grep NVMe
03:00.0 Non-Volatile memory controller: Micron Technology Inc 2550 NVMe SSD (DRAM-less) (rev 01) (prog-if 02 [NVM Express])
root@proxmox01:~# lspci -vvv -s 03:00.0 | grep Lnk
LnkCap: Port #1, Speed 8GT/s, Width x4, ASPM L1, Exit Latency L1 unlimited
LnkCtl: ASPM Disabled; RCB 64 bytes, LnkDisable- CommClk+
LnkSta: Speed 8GT/s, Width x2 (downgraded)
LnkCap2: Supported Link Speeds: 2.5-8GT/s, Crosslink- Retimer- 2Retimers- DRS-
LnkCtl2: Target Link Speed: 8GT/s, EnterCompliance- SpeedDis-
LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete+ EqualizationPhase1+
LnkCtl3: LnkEquIntrruptEn- PerformEqu-
I ran my t755 on a cheap DRAM-less NVMe drive, and that Crucial P3/Micron 2550 is a PCIe 4x4 capable drive.
For working with VM images using proxmox it's fine as-is, even with it running at PCIe 3x2, it can read/write at ~1200MB/sec...perfectly okay for what I need it to do. I can probably get it to run at x4 if I throw a heat sink on it and maybe remove the (unused) Mellanox ConnectX3-VPI off the PCIe slot so it's not dealing with its EM interference or thermals. But then, the t640/740 accepts SATA M2 and I am not sure if the t655/755 does or not (I don't remember testing for that). The fact that I have a stack of 64 and 256GB SATA M2s pulled from old/decommissioned Dell Latitudes meant that they are still very much useful for medium duty cases where a SATA3 SSD will work just fine.
So yeah, if you got the t655 for free or stupidly cheap, eh, maybe? Otherwise, just get a t640 with a USB-PD setup if you want cheap+functional, or an m75q if you want some decent staying power at a good price point - there are plenty of use cases where even the t640 is plenty for the needs.
