[SOLVED] ADATA XPG SX8200 slower speeds than was was written?

chocomintmichael

Prominent
Sep 25, 2019
76
2
545
The speeds stated on the website were a read speed of 3500m/s and a write speed of 3000 m/s. Obviously I don't expect it to actually match up to those speeds for the price point but they are significantly lower than what I expected.

Below I posted a picture of my speeds, wondering if this is weirdly low or is it normal?

EVkhLdU.png



Here's my entire build if you need it.

t0Q2yVt.png
 
Solution
Speed is correct for a 256GB drive. I'll even do the math for you since I'm crazy and like demonstrating how it works.

Sequential speeds are based on interleaving across multiple chips, each chip has multiple dies/dice, each die (32MB) has two or more planes. Here you have 8 dies (8x32 = 256GB) at two planes each. The smallest write operation is one page of data (16KB = .015625MB). The amount of operations per second is dependent on write latency (1 / wl), specifically SLC (single-bit) mode since this drive has SLC caching (~200µs or .0002 seconds). Therefore, the expected sequential write speed will be the number of planes times the page size in MB times how many times it can program that per second: voila. x = 1250 MB/s.

Your...

chocomintmichael

Prominent
Sep 25, 2019
76
2
545
The speeds stated on the website were a read speed of 3500m/s and a write speed of 3000 m/s. Obviously I don't expect it to actually match up to those speeds for the price point but they are significantly lower than what I expected.

Below I posted a picture of my speeds, wondering if this is weirdly low or is it normal?

EVkhLdU.png



Here's my entire build if you need it.

t0Q2yVt.png
 

USAFRet

Titan
Moderator
Did you clone from your previous 256GB SSD?
 
Speed is correct for a 256GB drive. I'll even do the math for you since I'm crazy and like demonstrating how it works.

Sequential speeds are based on interleaving across multiple chips, each chip has multiple dies/dice, each die (32MB) has two or more planes. Here you have 8 dies (8x32 = 256GB) at two planes each. The smallest write operation is one page of data (16KB = .015625MB). The amount of operations per second is dependent on write latency (1 / wl), specifically SLC (single-bit) mode since this drive has SLC caching (~200µs or .0002 seconds). Therefore, the expected sequential write speed will be the number of planes times the page size in MB times how many times it can program that per second: voila. x = 1250 MB/s.

Your speed is perfectly normal.

(P.S. read speed is done the same way but read latency is far lower than write. 4K Q1T1 is also different because while a 4KB read requires pulling the entire 16KB page, four 4KB writes can be done at once.)
 
Last edited:
Solution

chocomintmichael

Prominent
Sep 25, 2019
76
2
545
Did you clone from your previous 256GB SSD?
Nope fresh install!
 

chocomintmichael

Prominent
Sep 25, 2019
76
2
545
Speed is correct for a 256GB drive. I'll even do the math for you since I'm crazy and like demonstrating how it works.

Sequential speeds are based on interleaving across multiple chips, each chip has multiple dies/dice, each die (32MB) has two or more planes. Here you have 8 dies (8x32 = 256GB) at two planes each. The smallest write operation is one page of data (16KB = .015625MB). The amount of operations per second is dependent on write latency (1 / wl), specifically SLC (single-bit) mode since this drive has SLC caching (~200µs or .0002 seconds). Therefore, the expected sequential write speed will be the number of planes times the page size in MB times how many times it can program that per second: voila. x = 1250 MB/s.

Your speed is perfectly normal.

(P.S. read speed is done the same way but read latency is far lower than write. 4K Q1T1 is also different because while a 4KB read requires pulling the entire 16KB page, four 4KB writes can be done at once.)
Thank you for the detailed reply! Definitely taught me something new! Appreciate all the help.