Basically, there is no FAST control on RAW in any place around the world.  Basically you just CAN NOT directly use RAW file. They tend to use THM (JPEG) thumbnail file to do the preview, but when you are pulling the curves, they are recalculated and loading values from RAW, Reconvert to TIFF to show you on the screen.  Simply because we just can not read RAW from nake eye by all means.

Canon one is slower because the elaborate user interface also taking up huge amount of resources. Also, Canon will read into 100% JPEG file to do the process, therefore, it is slow.

BreezeBrowser on the other hand, will first convert RAW into JPEG, but swink the size to be perfect viewing on editing. However, once you are using ALT+T (Loading 100% JPEG), it will also recovert from RAW again and slow down the entire process as well.  Once again, it is a little faster, but not by a great deal.

If not 300D, Capture One will do the coversion first, and turn into very low resolution TIFF for editing.  This way it speeds up all the process, but you can probably never see the TRUE 100% TIFF until you do the conversion into physical files.  Which, is hard to tell colors, sharpness, and color accuracy will drop.  But you speed up your workflow.

What I do is to use BreezeBrowser to "BROWSE", and "VIEWING 100% pictures", then I go under Capture one to do the conversion and white balance.  However, both programs using different engine, colors may vary.

對不起我不大看得懂
我第一次借DSLR試用(300D)
用File Viewer將RAW檔存進硬碟之後
想用Photoshop開檔案來修圖卻什麼都讀不到
我應該怎麼做才對呢
Thanks!

有個軟體叫做Capture One！
它最近出了一個for digital rebel/300D版，
試用版連結如下：
http://www.pictureflow.com/CaptureOne/Pages/C1-Rebel-Purchase.html

有興趣的可以試試。