I bought this card as an upgrade for my low-profile Asus Radeon HD 6570 [model EAH6570/DI/1GD3(LP), to be exact] for use in my Dell OptiPlex 755. As stated in my review of the 6570, the OptiPlex 755 family has four issues that make it difficult to find a decent gaming card for them: (1) they're built using a BTX form factor and the first expansion slot is the PCI-E x16 slot, meaning that cards with double-wide brackets will not fit; (2) the Desktop (DT) and Small Form Factor (SFF) configurations can only utilize low-profile expansion cards; (3) roughly 1.3 cm to the right of the PCI-E x16 slot, there are several tall capacitors, meaning that video cards with wide heatsink/fan units will not work; (4) the PCI-E x16 slot will not necessarily supply 75W to a graphics card -- according to Dell, it's only specified for 25W operation. What this means for the OptiPlex 755 DT is that only single-wide, low-profile, low-power graphics cards are guaranteed to work.
The Sapphire Radeon HD 7750 Low Profile is an interesting card. It features a low-power example of AMD's Graphics Core Next (GCN) GPU architecture, which draws around 5W at idle and around 55W at load (in comparison, the Radeon HD 6570 draws around 5W at idle and around 50W at load). Within that power envelope, it crams 512 stream processors @ 800 MHz, 32 texture units, 16 ROPs, and 1GB GDDR5 @ 4.5 GHz on a 128-bit datapath. Both theoretically and in the real world, this makes the 7750 about twice as fast as the 6570 within roughly the same power envelope. Finally, the card is low-profile and has a (nearly silent) single-wide cooler. This makes is suitable not only for the OptiPlex 755 DT, but also the SFF and USFF variants.
I am pleased to note that the card works in my system beautifully, with zero power issues noted (the packaging on the card says that it requires a 400W power supply; given the low power nature of the 7750, this is simply not true). There have been no failures to power on, no random crashes, no overheating despite hours of burn-in testing and gaming. As I did with my Radeon HD 6570 review, I will make updates to this review at regular intervals throughout the year to report on how the card is holding up (and if any power problems did manifest themselves). Although the card itself only sports a DVI and a MiniDP connector, Sapphire also packages DVI-to-VGA and MiniDP to HDMI adaptors with the card -- you should be able to connect this card to any monitor you have without having to go out and buy additional adaptors. The card comes with the low-profile bracket preinstalled, but the full-profile bracket is also included.
Finally, let's talk performance. My OptiPlex 755 has a 3.0 Ghz Core 2 Duo E8400 with 6GB DDR2 SDRAM -- very adequate, but not by any means a powerhouse gaming build. The Radeon HD 7750 works wonders in this environment, allowing me to play all my games (Diablo III, Borderlands 2, Skyrim, The Last Remnant, Deus Ex: Human Revolution, etc.) at 1600x900 at max quality with antialiasing on in most cases, all at higher framerates than the 6570 was able to muster even at lower quality settings. The fan is whisper-quiet, and can only barely be heard at load. While it is possible to overclock this card, in the case of the OptiPlex 755 DT I wouldn't recommend it -- I'm not sure how well the power supply and the supposedly-25W-only PCI-E x16 slot would take it. In any case, that shouldn't be a problem -- even at stock speeds this is the fastest card compatible with the OptiPlex 755 DT by a country mile.
The competitors to the Radeon HD 7750 for the OptiPlex 755 DT include the Radeon HD 6570 (much slower), the Radeon HD 6670 (slower), and the Geforce GT 640 (about as fast as the Radeon HD 6670). While there exist exotic low-profile high-performance cards (Afox makes a low-profile Radeon HD 6870, for instance), these (a) do not fit within the physical confines of the OptiPlex 755 DT, (b) draw too much power for the OptiPlex 755 DT's power supply to handle, and (c) are so rare that they might as well not be available anyhow. In summary, this Sapphire Radeon HD 7750 is likely the highest-performance GPU option for the OptiPlex 755 DT/SFF/USFF at this point in time. As such, if you're looking for a gaming card for your OptiPlex, this card comes with my highest recommendation.
I am pleased to report no power issues over the last month and a half. I have had multiple play sessions lasting several hours apiece on a fairly regular basis, and the Radeon HD 7750 continues to soldier on like a champ. 1600x900 appears to be a very good sweet spot for this card, at least with the CPU and RAM I'm running. I've been able to run every game I've tried on high settings (max settings in some cases) at this resolution: XCOM: Enemy Unknown, Saints Row: The Third, Batman: Arkham City, X3 Reunion/Terran Conflict/Albion Prelude, The Witcher 2, etc. All of these games play as smooth as silk, without hiccups or stutters.
Interestingly enough, in the interim AMD has released the Radeon HD 7730 -- an even more cut-down version of the same chip that powers the Radeon HD 7770 and 7750. In terms of specs, it's actually a fairly close match to the older Radeon HD 6670: 384 stream processors, 24 texture units, 8 ROPs, and either 2GB DDR3 or 1GB GDDR5. Even with GDDR5 (which uses more power), the maximum TDP on this GPU is 47W -- a close match to the Radeon HD 6670 DDR3 (or 6570). If your computer's power supply is too low-power to handle the 7750 (and you do not have the option of swapping it out), definitely try out the 7730 instead.
The card continues to impress. I have had no power issues over this entire period, and with recent driver updates (Catalyst 13.11 beta) I've noticed a sizeable boost in performance in certain games (e.g. Saints Row: The Third, Saints Row IV). I have also experimented with overclocking, and am pleased to report that even fully overclocked (via the Catalyst Control Center), my system is fully stable even under load, and with a tangible across-the-board boost in graphical performance.
There has been some exciting news recently with the reveal of AMD Mantle -- a low-level graphical API for all GCN-architecture cards. It is likely that since the next generation of gaming consoles (Sony Playstation 4; Microsoft Xbox One) both utilize GCN-architecture GPUs, at least some major games will come over PC-side with enhanced performance for cards like this one. If that is the case, then this card becomes a phenomenal investment for the long-term.
Unless something drastic occurs, this will be my final update for this card. It has my highest recommendation for environments in which your power supply, physical space, or both are constrained. It runs 100% stable, even overclocked, on my Dell OptiPlex 755's 280W power supply. Its performance is top-in-class for my particular use case. It is very quiet, even under full load. And in the 4 months that I've had it, it has never once let me down. Thanks for reading my review -- I'm signing off.