• Welcome to TechPowerUp Forums, Guest! Please check out our forum guidelines for info related to our community.

PCIe NVMe Gen3 vs Gen4

Joined
Jul 9, 2016
Messages
357 (0.31/day)
System Name Gaming System
Processor i7-4960X
Motherboard ASUS Rampage IV Black Edition
Cooling Noctua NH-D15
Memory Corsair Vengeance LP 32GB DDR3
Video Card(s) EVGA GTX 1080 ti FTW3
Storage 1TB Samsung 850 EVO; 500GB Samsung 850 EVO
Display(s) HP zr2740w Surround
Case Corsair A540
Audio Device(s) onboard
Power Supply EVGA G2 1300
Mouse Logitech MK550
Keyboard Logitech MK550
Software Windows 10 Pro
Hi, I have not kept up with the NVMe or SSD tech. Does having a Gen4 NVMe SSD in a Gen3 slot will limit the performance of the Gen4 SSD? If so, by how much? I know Gen4 doubles the bandwidth, but does not only affect sequential read/write and not random read/write?
 

Mussels

Moderprator
Staff member
Joined
Oct 6, 2004
Messages
47,295 (8.66/day)
Location
Australalalalalaia.
System Name Big Fella
Processor Ryzen R7 2700X (stock/XFR OC)
Motherboard Asus B450-i ITX
Cooling Corsair H110 W/ Corsair ML RGB fans
Memory 16GB DDR4 3200 Corsair Vengeance RGB Pro
Video Card(s) MSI GTX 1080 Gaming X (BIOS mod to Gaming Z) w/ Corsair H55 AIO
Storage 1TB Sasmsung 970 Pro NVME + 1TB Intel 6000 Pro NVME
Display(s) Phillips 328m6fjrmb (32" 1440p 144hz curved) + Sony KD-55X8500F (55" 4K HDR)
Case Fractal Design Nano S
Audio Device(s) Razer Leviathan + Corsair Void pro RGB, Blue Yeti mic
Power Supply Corsair HX 750i (Platinum, fan off til 300W)
Mouse Logitech G903 + PowerPlay mousepad
Keyboard Corsair K65 Rapidfire
Software Windows 10 pro x64 (all systems)
Benchmark Scores Laptops: i7-4510U + 840M 2GB (touchscreen) 275GB SSD + 16GB i7-2630QM + GT 540M + 8GB
it halves the maximum bandwidth

how much it slows a drive will vary, but it will slow reads and writes to within the limits of the slot its placed in
 
Joined
Jul 9, 2016
Messages
357 (0.31/day)
System Name Gaming System
Processor i7-4960X
Motherboard ASUS Rampage IV Black Edition
Cooling Noctua NH-D15
Memory Corsair Vengeance LP 32GB DDR3
Video Card(s) EVGA GTX 1080 ti FTW3
Storage 1TB Samsung 850 EVO; 500GB Samsung 850 EVO
Display(s) HP zr2740w Surround
Case Corsair A540
Audio Device(s) onboard
Power Supply EVGA G2 1300
Mouse Logitech MK550
Keyboard Logitech MK550
Software Windows 10 Pro

Mussels

Moderprator
Staff member
Joined
Oct 6, 2004
Messages
47,295 (8.66/day)
Location
Australalalalalaia.
System Name Big Fella
Processor Ryzen R7 2700X (stock/XFR OC)
Motherboard Asus B450-i ITX
Cooling Corsair H110 W/ Corsair ML RGB fans
Memory 16GB DDR4 3200 Corsair Vengeance RGB Pro
Video Card(s) MSI GTX 1080 Gaming X (BIOS mod to Gaming Z) w/ Corsair H55 AIO
Storage 1TB Sasmsung 970 Pro NVME + 1TB Intel 6000 Pro NVME
Display(s) Phillips 328m6fjrmb (32" 1440p 144hz curved) + Sony KD-55X8500F (55" 4K HDR)
Case Fractal Design Nano S
Audio Device(s) Razer Leviathan + Corsair Void pro RGB, Blue Yeti mic
Power Supply Corsair HX 750i (Platinum, fan off til 300W)
Mouse Logitech G903 + PowerPlay mousepad
Keyboard Corsair K65 Rapidfire
Software Windows 10 pro x64 (all systems)
Benchmark Scores Laptops: i7-4510U + 840M 2GB (touchscreen) 275GB SSD + 16GB i7-2630QM + GT 540M + 8GB
the gen 3 4x slots can do around 4GB/s (3.5GB/s seems to be closer to reality)
gen 4 4x slots can do around 8GB/s, but no drives max it out yet


halving the bandwidth to the slot doesnt mean the drives run at half speed
 
Joined
Jul 9, 2016
Messages
357 (0.31/day)
System Name Gaming System
Processor i7-4960X
Motherboard ASUS Rampage IV Black Edition
Cooling Noctua NH-D15
Memory Corsair Vengeance LP 32GB DDR3
Video Card(s) EVGA GTX 1080 ti FTW3
Storage 1TB Samsung 850 EVO; 500GB Samsung 850 EVO
Display(s) HP zr2740w Surround
Case Corsair A540
Audio Device(s) onboard
Power Supply EVGA G2 1300
Mouse Logitech MK550
Keyboard Logitech MK550
Software Windows 10 Pro
Thank you, that is exactly the info I am seeking. Seems like with the Corsair drive I can max out the bandwidth.
 
Joined
Nov 11, 2004
Messages
4,038 (0.74/day)
Location
Formosa
System Name Overlord Mk MX
Processor AMD Ryzen 7 3800X
Motherboard X570 Aorus Master
Cooling Corsair H115i Pro
Memory Viper Steel DDR4 3800MHz 16-19-16-19-36
Video Card(s) Gigabyte RTX 2080 Gaming OC 8G
Storage 1TB WD Black NVMe (2018), 2TB Viper VPN100, 1TB WD Blue 3D NAND
Display(s) Asus PG27AQ
Case Corsair Carbide 275Q
Power Supply Corsair RM750
Mouse Logitech G500s
Keyboard Wooting Two
Software Windows 10
Benchmark Scores https://valid.x86.fr/ztiub6
Thank you, that is exactly the info I am seeking. Seems like with the Corsair drive I can max out the bandwidth.
Maybe, but only in sequential data transfers.
I would avoid the first generation of PCIe 4.0, as they rely on a modified PCIe 3.0 controller with a faster bus and no other enhancements. They also run quite hot.
 
Joined
Sep 11, 2019
Messages
30 (3.00/day)
Processor i7 - 9700K
Motherboard Asus H370M Plus
Cooling Arctic Freezer 13
Memory 32GB G-Skill @ 2666Mhz CL15
Video Card(s) 5700 XT (Gigabyte Aftermarket)
Storage 970 EVO 500GB, 860 EVO 2TB, 840 Pro 256GB
Display(s) Samsung C32HG70 - 1440p, Freesync 2
Case Silverstone GD-07B
Audio Device(s) Schiit Modi 2 Uber - Schiit Magni 2 Uber - Sennheiser HD595's
Power Supply Seasonic S12II 620W
Mouse Steelseries Sensei 310
Keyboard Corsair K70 LUX (Brown Switches), Razer Orbweaver Chroma Stealth
Correct, it only caps the maximum bandwidth of the SSD, assuming the drive is capable of exceeding PCIe 3.0 x4 speeds in the first place. It shouldn't have any effect on random I/O.

In fact, on a couple occasions I've used inexpensive PCIe adapter cards to run M.2 drives on older PCIe 2.0 motherboards which didn't have native M.2 slots, and still saw significant improvement over the early 120GB SATA SSDs they were running. The vast majority of the benefit is coming in at below even PCIe 2.0 (or PCIe 3.0 x2) bandwidth.
 
Top