Mero OPT(12 months) June 17 ma expire  hudai chha. I applied for 17 month extension on April 1st  but I was just notified of RFE yesterday. I don't know the reason for RFE yet. 

Today I got a job offer from another company ( I am sure the company is e-verified)  and I plan on starting from June 3. Am I  going to have any problem switching the company before OPT extension is approved. I plan on talking with International Services of my school soon but just wanted to check if any one on here has gone through similar situtaion like me. 

Also, does anyone know how long it takes to get RFE mail. And how long USCIS take to make decision once they receive RFE material. I know it is going to different for everyone but just wondering if somone had to go through similar situation. 

You can continue to work for additional 4 months (120 days), after you have applied for OPT Extension and its pending.  You can talk to your International office and they will tell you the same.

 So, does it matter if I change my employer?

I don't think it matters.

http://webs.wichita.edu/?u=INTL&p=/Current_Students/Opt_Ext/OptExt5/

Try this link here. It talks about it briefly.

 OPT extension requires e-verify number of your employer. My spouse also got RFE during extension because the e-verify number he provided wasn't correct (his employer didn't know which number it was, so gave the wrong number). But, once he provided the correct number, his extension was approved within a week they received it. He received RFE by mail within a couple days of it appearing in the USCIS website, sent new info the next day it was received.
I have also heard of other people receiving RFE for fingerprint if you submitted the application online, and even in their cases, extension was approved about a week after responding. 

Since you don't know what the RFE is for, I think the best thing for you to do is to wait for it. Explain the situation to your (potentially) new employer and buy some time if possible. And then take steps depending on what the RFE is for. If it is something minor, it should be cleared pretty easily. But, since the extension is based on your current employer's e-verify status, I think it is best if you change job once you get the extension. 

 I am thinking of waiting for OPT extension approval too but I don't think the new company will wait for me. There isn't exact time frame that i can provide to the new company and they are looking for someone to start as soon as possible. 
I would hate to lose this opportunity the company that is offering me job is better in every way  than the company I am working right now. 

 I don't know if anyone cares but here is what I found after calling my international student services. They didn't have an answer right away so they told they will inform me after they find the right process. After couple of hours they emailed me. 

“A student may change employers during the 17-month period, but all employers that a student will work for during the STEM extension period must be registered in the DHS E-Verify program, and the student must report the change in employment to his or her DSO.”

I replied back "What about changing the employer before the 17-month period has started and application for 17 month extension is pending?"
You just need to report when you terminated your employment with the previous employer and report the name, address, contact information and start date with the new employer.

Thank you  everyone who took time to reply to my post!