Thinkpads Forum

Hi All,

Until recently my T480s had a 256GB Kioxia BG5 series SSD (KBG50ZNS256G) with PCIe4x4 with the following random read/write speeds measured with Crystal Disk Mark 8 for Q=1 & T=1:
- Read: RND 4KiB (Q= 1, T= 1): 57.662 MB/s [ 14077.6 IOPS] < 70.78 us>
- Write: RND 4KiB (Q= 1, T= 1): 104.442 MB/s [ 25498.5 IOPS] < 38.96 us>

When upgrading it to a 1TB Kioxia Exceria Plus G4 series SSD (LVD10Z001T) with PCIe5x4 I was anticipating a big increase in these figures as per this SSD's specs promising up to 1.3M/1.4M IOPS max for random read/write speed resp., but hardly got any:
- Read: RND 4KiB (Q= 1, T= 1): 64.570 MB/s [ 15764.2 IOPS] < 63.16 us>
- Write: RND 4KiB (Q= 1, T= 1): 102.007 MB/s [ 24904.1 IOPS] < 39.86 us>

Should this have been reasonably expected with T480s? I suppose it's not T480s's PCIe3x4 capping my random read/write speeds at those modest figures?


Thanks in advance!

T480s's PCIe3x4 is capping speeds.
Buy a faster Thinkpad if you need those new speeds.

RealBlackStuff wrote: ↑

Thu Feb 12, 2026 2:23 am

T480s's PCIe3x4 is capping speeds.

Thank you: looks like it was capping even the old SSD's random speeds then, as they're supposed to reach 350K/360K IOPS for random read/write resp.

RealBlackStuff wrote: ↑

Thu Feb 12, 2026 2:23 am

Buy a faster Thinkpad if you need those new speeds.

Due to fairly light use (e.g. no gaming) I'm perfectly fine with them, and also am too happy overall with my T480s to complain: still believe it was really good value for money at £170 ~3yrs ago.