problem with large arrays in php 4.3.2

Hello, I have an old version of php (4.3.2) that is acting rather strangely. I'm searching two large arrays (approx 22,000 records in each) using array_diff_key() from the PEAR PHP_Compat library: $result = $args[0]; foreach ($args[0] as $key1 => $value1) { for ($i = 1; $i !== $array_count; $i++) { foreach ($args[$i] as $key2 => $value2) { if ((string) $key1 === (string) $key2) { unset($result[$key2]); break 2; } } } } And I'm getting aweful performance. I know it's a ton of records (22,000 * 22,000), but it shouldn't take 16 minutes on a P4 Xeon 2.4ghz! Has anyone seen this before? Is this a bug? Or are my math skills lacking and this is perfectly normal performance for the size of the data set? Thanks! -- Jesse Guardiani Programmer/Sys Admin