Retainability dropped after HSUPA 5.8 enabled

[Rifa]

Dear Guru's,
I would like to seek some advice on how to fix a degradation on the retainability (RNC_609A) after activating the feature HSUPA 5.8. Any advice on what should I look for or what could be the problem? Appreciate your kind advice.
Thank you,

[3gpp]

Perhaps 2ms EDCH TTI is not functioning well on some UE models.

[ninjafine]

Dear Guru's,
I would like to seek some advice on how to fix a degradation on the retainability (RNC_609A) after activating the feature HSUPA 5.8. Any advice on what should I look for or what could be the problem? Appreciate your kind advice.
Thank you,

Hi! You may also check if RSSI and UL channel elements consumption is increased dramatically.
Thanks and reps are appreciated.