Don't blame me if you don't agree, blame the person doing the teardown. From the video at 5:30.
Read speeds aren't 5.5 GB/s but they are "as fast as" 5.5 GB/s. Or as I stated, up to 5.5 GB/s.
Perhaps there was an error in translation but for the English language, "as fast as" is the same as "up to".
Regards,
SB
Lets use the language he actually used in the video instead of relying on translating.
カスタムのSSDコントローラーにより読み込み速度は生データの転送速度で毎秒5.5 GBと大速化されゲームのロード時間を大幅にたんしゅくしています。
I don't think he used "up to" or "as fast as", just states the read speed is 5.5 GB/s and can reduce load speeds a lot.