[Wine] Question on Wine CPU usage

[cnbiz850]

I made some simple comparisons about CPU usages between running Wine and running XP on a VirtualBox.  In both cases, I ran exactly the same 2 applications with about the same configuration.  The Wine I use is 1.3.26.  The XP is XP Home with SP2 but trimmed down to nearly its bare-bones (having only the possibly minimum number of services running).  The computer is a Dell Studio laptop with "Intel Core 2 Duo CPU P8700 2.53GHz" and 4GB of RAM running Ubuntu 10.10 64bits.  The virtual machine for XP is configured to use 1 CPU and 512MB of RAM.  Separately, I used "top" to measure the CPU usages.  Results are as follows:

These numbers are from running Wine:

Code:
  PID USER          PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND            
13770 cnbiz850      20   0 2665m 110m  15m S   16  2.8   1:12.70 mytrader2009.ex    
14073 cnbiz850      20   0 2632m  60m  11m S   14  1.5   0:45.51 TradeBlazer.exe    
14230 cnbiz850      20   0  9036 6080  708 S   10  0.2   0:29.95 wineserver                          
13773 cnbiz850      20   0  7084 4356  692 S    6  0.1   0:35.47 wineserver         
14258 cnbiz850      20   0 2603m  31m  14m S    2  0.8   0:06.99 tbdatacenter.ex    




The following numbers are from running XP:

Code:
  PID USER          PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND            
20603 cnbiz850      20   0 1268m 649m 599m S   23 16.5   3:56.50 VirtualBox         




Notice the difference in CPU usage is pretty significant.  In the Wine case, total is about  48%, and in XP' case, it is 23%.

I have been under the impression throughout the years that Wine uses much less resources than using a virtual machine, and also feel that I understand that in theory.  But can anyone please explain about the above results?  Is there anything wrong, or am I missing something?