There are many reasons why store.exe would use lots of memory. The strangest one i have found recently was failed backups.
After performing a backup of the mailbox databases the memory utilisation of store.exe dropped from 15.6Gb to 2.9Gb.



Click OK and then Next. Click New and then Finish to complete this process.
These are the default settings. To configure Maximum outgoing message size, we use the -MaxSendSize switch. Microsoft has been kind enough to allow us to specify the units we are working with, ie: kb, mb, gb or tb. Kilobytes is assumed if no unit is specified. So we could change the outbound message size to a 10Mb limit by typing: Set-TransportConfig -MaxSendSize 10mb


Now we get started with some almost difficult command-line stuff. If you started out with ms-dos you should feel quite at home. First we need to set the web services virtual directory internal and external url's. Type Get-WebServicesVirtualDirectory and press enter.
(tip: if you type get-web and press Tab, it will auto-complete for you.)
Click the top-left corner of the shell box, hover your mouse over edit and click mark.
Create a block by selecting all the text and then press enter. Open notepad and paste the text.
Edit the Internalurl to reflect the common name you registered in the certificate. Select this url and click edit and then copy.
Go back to the shell. type:
Set-ClientAccessServer -AutoDiscoverInternalUri 'https://thenameonyourcert/autodiscover/autodiscover.xml'
Set-WebServicesVirtualDirectory -InternalUrl 'https://thenameonyourcert/EWS/Exchange.asmx' -Identity 'servername\EWS (Default Web Site)'
Next we set the Outlook Address Book internal url:
Set-OabVirtualDirectory -InternalUrl 'http://thenameonyourcert/OAB'
Next we set the Outlook Web Access internal url:
Set-OabVirtualDirectory -InternalUrl 'http://thenameonyourcert/OAB'
and finally we set the autodiscover url:
Set-AutodiscoverVirtualDirectory -InternalUrl https://thenameonyourcert/Autodiscover/Autodiscover.xml -Identity 'servername\Autodiscover (Default Web Site)'
Ok, certificates all done. Now open Exchange Management Console. and enable Outlook anywhere.
You will be prompted for the external address. You need to specify the name on your certificate.
Once successfully installed. Your Outlook Anywhere or RPC over HTTPS is configured and ready to use.
Select Certificate Services, and click Details. Click in the Select box for Certificate Services CA, you will be shown a dialog box warning that you will not be able to change the name of the server once you install the certificate services. Click Yes and then OK. Click Next. Choose Stand-Alone Root CA and click next. Enter the name of your CA. You can call it whatever you like really. Click Next. Verify the path of the certificate database and log and click next.
You will get a dialog box warning that IIS will be stopped temporarily. Click Yes. Windows will then copy some files, so make sure you have you Windows Server 2003 Disk 1. You may be warned that ASP needs to be enabled on IIS, choose Yes. Click Finish when it's all done.
Next we can get CA Services to automatically issue the certificates on request. In administrative tools, Select Certificate Authority. Right-click "Certificate authority (local)" and click properties. On the Policy Module tab select Properties and choose "follow the settings in the certificate template, if applicable. Otherwise, automatically issue the certificate." and click ok. The certificate services will restart. Close the Certificate Authority.

Ok, CA installed. NExt step is to request a certificate.
Open Internet Information Services Manager from Administrative Tools. Expand your server name and websites. Right-click "Default Web Site" and click properties. On the Directory Security tab, click Server Certificate.

Click Next, select Remove the Current certificate and click next twice and then finish. Click Server Certificate again. Click next. Choose Create a new certificate and click next. Choose Prepare the request now, but send later. Click Next. Accept the Default name and bit length and click next. Enter you organisation information and click next. Now the next step is very very important. Here you enter the common name. This is the name you will enter into your browser to connect to you outlook web access. This name should be a public name. I'm using webmail.rndorg.net - If you get this wrong, your certificate will be useless and you will have to start again. So enter the name and click next. Choose your country, state/province and city/locality and click next. Accept the default name and path and click next twice and then finish.
Now we need to submit the request to the Root CA. To do this we go into internet explorer. and navigate to http://caservername/certsrv
Click Request a certificate. and then advanced certificate request. Choose the second option, "Submit a certificate request by using .... PKCS #7 file." You can either browse for the file to insert or open c:\certreq.txt in notepad, select the text, copy and paste it into the block provided. and then submit.
Go back into Certificate Authority from the Adminstrative tools menu. Expand root CA and then pending requests. Select the right-click the certificate on the right and click all tasks - and then issue. Close the CA. Go back into internet explorer and back to http://caservername/certsrv/
Click View the status of a pending certificate request. and then saved request (and the date).
Click download the certificate. select the same location as your certificate request.
Go back into IIS management. Right-click default web site and click properties. Select the Directory Security tab and then click server certificate. Click next. and then ensure process the pending request and install the certificate is selected and click next. click browse and locate the certnew.cer file you saved earlier. Click next and accept port 443, click next twice and then finish. Close IIS Management. Well done, you now have a web server certificate all installed and ready to go.