Server Freezes During Curl Command

I have a script that does a PHP Curl call where it downloads a large file (~20meg) to the local server.

While its doing the Curl Call, I open up a new window and keep working with the site, (ie. opening a simple image) and the browser keeps saying "Waiting for reply". As soon as the Curl Call stops, then the server works again.

What could course this?

The server is dedicated and only me using it:
Intel Core2Quad Q6600
2GB DDR RAM
Linux - CentOS 5 32bit

While its doing the curl call, I ran uptime and the load is 0.0 0.0 0.0.

From my PHPINFO:

Code:
Apache Version Apache/1.3.39 (Unix) mod_ssl/2.8.30 OpenSSL/0.9.8b
Apache Release 10339100
Apache API Version 19990320
Hostname:Port localhost:80
User/Group apache(100)/500
Max Requests Per Child: 1000 - Keep Alive: off - Max Per Connection: 100
Timeouts Connection: 120 - Keep-Alive: 1
Server Root /etc/httpd
Loaded Modules mod_php5, mod_ssl, mod_setenvif, mod_so, mod_headers, mod_expires, mod_auth_anon, mod_auth, mod_access, mod_rewrite, mod_alias, mod_userdir, mod_actions, mod_imap, mod_asis, mod_cgi, mod_dir, mod_autoindex, mod_include, mod_info, mod_status, mod_negotiation, mod_mime, mod_log_referer, mod_log_agent, mod_log_config, mod_env, mod_vhost_alias, http_core
HTTP_CONNECTION Keep-Alive
php.ini

Code:
max_execution_time = 1000 ; Maximum execution time of each script, in seconds
max_input_time = 1000 ; Maximum amount of time each script may spend parsing request data
;max_input_nesting_level = 64 ; Maximum input variable nesting level
memory_limit = 128M ; Maximum amount of memory a script may consume (128MB)
[MySQL]
; Allow or prevent persistent links.
mysql.allow_persistent = Off

; Maximum number of persistent links. -1 means no limit.
mysql.max_persistent = -1

; Maximum number of links (persistent + non-persistent). -1 means no limit.
mysql.max_links = -1

httpd.conf

Code:
MinSpareServers 5
MaxSpareServers 10
StartServers 5
MaxClients 150
MaxRequestsPerChild 1000
httpd-mpm.conf - changing this made no difference

Code:
<IfModule mpm_prefork_module>
StartServers 30
MinSpareServers 10
MaxSpareServers 20
MaxClients 200
MaxRequestsPerChild 0
</IfModule>