Getting performance issues with SetTexture()

[Tercioo]

Hey folks.
I'm getting fps drops from 90fps to 7fps when i do use SetTexture() with a .tga file equal or larger than 256x256.
Since it seems a odd issue, I'm wondering if this is happening only for me, may you guys test this too?

To try reproduce on your guys end, create a 1024x1024 .tga texture or use this https://www.dropbox.com/s/ulyeqa2z0ummlu7/1024.tga?dl=0, place it on world of warcraft/interface/

And run the macro:
/run for o=1,10 do local f=CreateFrame("frame");f:SetPoint("center");f:SetSize(300,300); local t=f:CreateTexture(nil,"overlay");t:SetAllPoints();f:SetScript("OnUpdate",function() t:SetTexture("Interface\\1024")end);end;

Thank you.