In the past, I reviewed SilverStone Extreme 850R Platinum, an exceptional performer PSU in the SFX segment. This previous variant was ATX 3.0 compliant (latest for its time) and now SilverStone has relaunched this SFX PSU with even more Rizz, I mean with ATX 3.1 specs and calling it SilverStone Extreme 1000Rz (maybe that’s what Rz stands for).
There’s no significant difference between ATX 3.0 & ATX 3.1 specs and both of them are backwards compatible, only major changes are: slight improvement on 12VHPWR connector – now referred to as 12V-2×6 connector, for partial or loose connection detection along with 0.25mm increase for 12V & GND pins, which add further safety to prevent connector melting, and lastly reducing down the Hold-up time (by using low capacity uF rating bulk capacitor/s) which lowers down the overall cost and also adds in a little more efficiency. The later change for the Hold-up time is more of a downgrade and it’s highly discouraged by professional reviewers, but for the end-user it’s really not going to matter that much.
So for its new ATX 3.1 revision, SilverStone Extreme 1000Rz should perform pretty much identical to its older variant, SilverStone Extreme 850R.
Here are the specifications:
| Specification | Detail |
|---|---|
| Product Name | SST-EX1000R-PM |
| Model Number | SST-EX1000R-PM |
| Dimensions (W x H x D) | 125 mm × 63.5 mm × 100 mm |
| DC Output Cable | Fully Modular |
| ATX12V Version | ATX v3.1 / SFX v4.1 |
| Efficiency Certification | Cybenetics Platinum (89.988% @115V, 91.830% @230V) |
| Max DC Output | 1000W |
| Power Density | 1260.8 W/L |
| Combined +3.3V & +5V | 100W |
| Combined +12V | 1000W (Single Rail) |
| High-Power Connectors | 2× EPS, 4× PCIe 6+2-pin, 1× PCIe 12+4-pin (600W) |
| Peripheral Connectors | 4× SATA, 3× Molex, 1× FDD |
| Fan Type | 92mm Fluid Dynamic Bearing Fan |
| Fanless / Semi-Passive Mode | Yes (Selectable) |
| Noise Level |
|
| Operating Temperature | 0 – 50 °C (Continuous Full Load) |
| Weight | 1.02 kg (2.25 lb) |
| Warranty | 5 Years |
Packaging & Unboxing
Design
Cable & Connectors
| Connector Type | Quantity |
|---|---|
| Motherboard cable (24/20-pin) | 1x |
| CPU / ATX 12V connectors (4+4-pin) | 2x |
| PCI-E 12V-2×6 connector (600W) | 1x |
| PCI-E connectors (6+2-pin) | 4x |
| SATA connectors | 4x |
| PATA (Peripheral) connectors | 3x |
Teardown & Component Analysis
Just like we saw in the previous version, SilverStone has once again opted for the same OEM High Power/Sirfa for 1000Rz. We see the same densely populated SFX platform with APFC Boost + Half-Bridge LLC topology.
The primary heatsink takes up much of the space as it incorporates all the major power components like a single Bridge Rectifier, single APFC TO-247 package MOSFET (which is much beefier than traditional TO-220 package MOSFET), Single APFC Boost Diode and two LLC MOSFETs that make Half-Bridge. This aluminium heatsink’s fins are well spread out and thanks to 1000Rz’s extremely high rizz I mean efficiency, this will be more than adequate but we may see higher fan speed which is quite common in this tiny form factor PSU.
This design of the main transformer has sort of become a new industry norm these days as we have been seeing it quite often in many of our PSU teardowns. This Planar-like design transformer utilizes flat copper planes instead of traditional copper enamel wires, which provides much larger surface area, greatly reducing the size and increasing the operating frequency. Those big copper planes inside the transformer also help soaking in the generated heat, requiring no need for the vertically mounted heatsinks in the close proximity to the main transformer.
6x 12V rail MOSFETs are soldered on the back of the PCB, they get cool down by the PSU chassis itself with the help of a thick thermal pad.
The main Bulk electrolytic capacitor is from Japanese manufacturer Nippon-Chemicon and surprisingly, as we stated above the downgrade of Hold-up time in ATX 3.1 specs, the capacitor is rated only 560uF! This is way too less of a capacity for a 1000W rated PSU but again, ATX 3.1 specs have loosen up its grip for the Hold-up up time so all is fine I guess. Hold-up time matters when you have applied maximum load on the PSU and then you get hit by some power hiccups (micro power outages for a few milliseconds) or when you lose power from the main grid and your UPS takes a few milliseconds to switch over to the battery power. You either need to have a very capable UPS or need <800W total system load to be not bothered by this low Hold-up time provided by this lower capacity rated bulk capacitor.
Rest of the electrolytic as well as polymer capacitors are also from well reputable Japanese brands. No compromises on quality here!
A single vertical daughter board is mounted near the main transformer for 5V & 3.3V minor voltage rails.
A 92mm FDB fan from Globe Fan. This seems to be a 3-pin PWM fan (unlike DC controlled 2-pin fan) so we may see better performance in terms of fan noise. I recently reviewed a (Hyperlinked) Lian Li SP1000P SFX PSU that was utilizing the same dimension 92mm size fan but with 2-pin design and it was very loud during heavy loads.
There’s a Hybrid-Fan mode switch on the back of the PSU which in my test, only kicked-in the fan when the load exceeded ~250W of load.
There’s a very unique feature that I have observed in SilverStone’s SFX PSUs – when you turn off the PSU, regardless if its fan is spinning or not, it immediately kicks-in the fan for exactly 2-minutes to cool down the internals. This can significantly increase the lifespan of the PSU. A very well-thought-out and impressive attention to detail.
PSU Load Testing
Voltage Regulation
| Load in % | 12V Rail | 5V | 3.3V |
|---|---|---|---|
| 20% | 12.16 | 5.04 | 3.30 |
| 50% | 12.09 | 5.04 | 3.29 |
| 70% | 12.05 | 5.03 | 3.29 |
| 90% | 12.01 | 5.03 | 3.29 |
| 100% | 12.01 | 5.03 | 3.29 |
Voltage regulation is good, we have seen better results in this specific test but keep in mind this is an SFX PSU so you may not be pushing this to its max limits anyway.
PSU Efficiency
| Load in % | Efficiency | Power Factor |
|---|---|---|
| 20% | 92.03% | 0.956 |
| 50% | 94.16% | 0.990 |
| 70% | 93.85% | 0.995 |
| 90% | 93.52% | 0.996 |
| 100% | 93.19% | 0.996 |
Again, we see a little improvement in efficiency numbers compared to the previous 850R PSU. Getting improvements for a 1000W rated PSU over an 850W is quite impressive. 94% efficiency for 50% of the rated power is exceptional!
Voltage Ripple Performance
| Load in % | 12V Ripple |
|---|---|
| 20% | 17.6 |
| 50% | 24.8 |
| 70% | 28 |
| 90% | 28.8 |
| 100% | 29.6 |
There’s a very slight improvement in voltage ripple performance compared to its older 850R SFX variant and it’s very good for an SFX PSU especially with 1000W rating.
Temperature
SilverStone Extreme 1000Rz ran with decent noise levels throughout different load variations and the fan speed was well controlled. Its exceptional Platinum efficiency and better fan speed management easily puts this PSU among the top performers in terms of noise for an SFX PSU.
As we have seen above, due to the mounting of the 12V rail MOSFETs on the back, the max temperature is hitting 64.3C on full load. For an average user, hitting max 1000W load on his/her mini ITX PC is going to be very unlikely IMO. But if you do, the fan noise can get to a much more audible level.
Should You Buy it?
Buy It If
✅ You’re building a long-term SFF system: The SilverStone Extreme 1000Rz is an excellent choice for small form factor builds that need enough power to comfortably support multiple generations of high-end GPUs and CPUs over the next 5–6 years.
✅ You want a quiet SFX PSU: SFX power supplies are often criticized for high noise levels, but the Extreme 1000Rz keeps fan noise impressively well-controlled, even under sustained gaming or workstation loads.
✅ You want strong value in the SFX category: While SFX PSUs naturally command a price premium, SilverStone has priced the Extreme 1000Rz competitively compared to other 1000W SFX units from rival brands.
Don’t Buy It If
❌ You expect premium extras and aesthetics: Although SilverStone delivers excellent raw performance, competing brands now offer additional features such as white color variants, improved cable management accessories, and dual-color 12V-2×6 connectors for enhanced safety, all of which are missing here.
My Final Thoughts
I have literally lost count of how many times I have reviewed PSUs from SilverStone, but every time I test and review their PSUs, I am always satisfied with their top-tier level performance. SilverStone has become more of a Noctua of PSU brand, they only mean best and impressive performance with a simple and minimalist design approach.
