Registry entries shared by:

MSFTPSVC FTP Service
GOPHERSVC Gopher service
W3SVC   WWW service

are located at:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\InetInfo\Parameters

 Value   Default   D e s c r i p t i o n 
 AcceptExOutstanding   40   The minimum number of idle sockets maintained when using AcceptEx, an IIS optimizing feature that allows IIS to establish a new connection and read its initial data request in the same step. The range is 0-1000. 
 AcceptExTimeout   0x78
(120 seconds)
 
 The length of time an AcceptEx socket waits for operation completion. Limiting the time improves overall performance and reduces memory usage. 
 BandwidthLevel   0xFFFFFFFF   Limiting bandwidth prevents IIS from using a disproportionate share of the network when it sends data. The default does not limit bandwidth. If the bandwidth approaches the limit you set, it is throttled back. 
 CacheSecurityDescriptor   0   0=IIS retrieves each object to check user rights. 1=IIS caches objects so they don't have to be re-retrieved. 
 DisableMemoryCache    0   0=IIS caches objects to improve performance. 1=IIS is slow. 
 ListenBackLog   15   If the server is rejecting requests when it is most active, increase this value. The max is 250. 
 LogFileBatchSize   0x40 (64KB)   Signals when to write a logfile record. Larger values improve performance at the expense of memory. 
 LogFileFlushInterval   0x12C
(300 Seconds)
 
 A value of 0xFFFFFFFF never forces the log. It waits for the batch size. Lower values are designed for less active servers.  
 MaxPoolThreads   0xA (10)   20 threads are maximum. 
 MemoryCacheSize   10% of
memory
 
 A value of 0 disables the cache (bad idea) while any other value in bytes is valid. 
 MinFileKbSec   1000   The greater of ConnectionTimeout or File size divided by this value, calibrated in seconds, is the maximum time that IIS will allow to send a file. The largest number you can use is 8192. 
 ObjectCacheTTL   0x1E
30 seconds
 
 0=IIS does not cache. 0x1-0x7FFFFFFF is the maximum time an inactive object can remain in cache. 0xFFFFFFFF=An object remains in cache until it is overwritten. 
 PoolThreadLimit   MB of RAM*2   This value is optimal for most systems and changing it might impair performance. 
 ThreadTimeout    0x 15180
86,400 sec.
 
 Inactive I/O threads that exceed this limit are stopped. 
 UseAcceptEx   1   0=AcceptEx is disabled.1=AcceptEx is enabled. 
 UserTokenTTL   0x384
900 seconds
 
 0=security tokens are not cached. This value determines how long an unreferenced security token remains in the cache. 

You must reboot the server for any changes to take effect.