How to speed up Magento(1.7) Backend

[magentoexperts]

Since you have APC installed, then there should not be anything wrong with the server, maybe you should check for malware sometimes hackers can leave malware into a application and this can slowdown the system, so possibly you should check the code for this.

[Rob Staff]

We use Brims Full Page Cache on our sites and notice huge improvements on performance and keep you logs clean as other mentioned. You can find Brims FPC on magento connect.