This patch is experimental as it's based on undocumented (officially) functions in aticonfig, however it should work fine on any HD series ATI card.
The arguments to aticonfig were obtained from here: http://www.phoronix.com/forums/showp...2&postcount=18

This patch will read the GPU temp, current 3D clock and default 3D clock (there's all sorts of other info it could read, but let's start simple).

Code:
diff --git a/pts-core/functions/pts-functions_system_graphics.php b/pts-core/functions/pts-functions_system_graphics.php
index 84de190..fa1c696 100644
--- a/pts-core/functions/pts-functions_system_graphics.php
+++ b/pts-core/functions/pts-functions_system_graphics.php
@@ -26,10 +26,15 @@ function pts_record_gpu_temperature()
 }
 function graphics_processor_temperature()
 {
-       $temp_c = read_nvidia_extension("GPUCoreTemp");
+       $temp_c = -1;

-       if(empty($temp_c))
-               $temp_c = -1;
+       $nv_temp_c = read_nvidia_extension("GPUCoreTemp");
+       $ati_temp_c = read_ati_extension("CoreTemperature");
+
+       if(!empty($nv_temp_c))
+               $temp_c = $nv_temp_c;
+       elseif(!empty($ati_temp_c))
+               $temp_c = $ati_temp_c;

        return $temp_c;
 }
@@ -145,13 +150,20 @@ function graphics_processor_stock_frequency()
        $core_freq = 0;
        $mem_freq = 0;

-       $freq = read_nvidia_extension("GPUDefault3DClockFreqs");
+       $nvfreq = read_nvidia_extension("GPUDefault3DClockFreqs");
+       $atifreq = read_ati_extension("Stock3DFrequencies");

-       if(!empty($freq)) // NVIDIA GPU
+       if(!empty($nvfreq)) // NVIDIA GPU
+       {
+               $nvfreq = explode(',', $nvfreq);
+               $core_freq = $nvfreq[0];
+               $mem_freq = $nvfreq[1];
+       }
+       elseif(!empty($atifreq)) // ATI GPU
        {
-               $freq = explode(',', $freq);
-               $core_freq = $freq[0];
-               $mem_freq = $freq[1];
+               $atifreq = explode(',', $atifreq);
+               $core_freq = $atifreq[0];
+               $mem_freq = $atifreq[1];
        }

        return array($core_freq, $mem_freq);
@@ -161,13 +173,20 @@ function graphics_processor_frequency()
        $core_freq = 0;
        $mem_freq = 0;

-       $freq = read_nvidia_extension("GPUCurrentClockFreqs");
+       $nvfreq = read_nvidia_extension("GPUCurrentClockFreqs");
+       $atifreq = read_ati_extension("Current3DFrequencies");

-       if(!empty($freq)) // NVIDIA GPU
+       if(!empty($nvfreq)) // NVIDIA GPU
+       {
+               $nvfreq = explode(',', $nvfreq);
+               $core_freq = $nvfreq[0];
+               $mem_freq = $nvfreq[1];
+       }
+       elseif(!empty($atifreq)) // ATI GPU
        {
-               $freq = explode(',', $freq);
-               $core_freq = $freq[0];
-               $mem_freq = $freq[1];
+               $atifreq = explode(',', $atifreq);
+               $core_freq = $atifreq[0];
+               $mem_freq = $atifreq[1];
        }

        return array($core_freq, $mem_freq);
diff --git a/pts-core/functions/pts-functions_system_parsing.php b/pts-core/functions/pts-functions_system_parsing.php
index 1d0cb7f..75197b0 100644
--- a/pts-core/functions/pts-functions_system_parsing.php
+++ b/pts-core/functions/pts-functions_system_parsing.php
@@ -159,5 +159,50 @@ function read_nvidia_extension($attribute)

        return $nv_info;
 }
+function read_ati_extension($attribute)
+{
+       $ati_info = "";
+
+       //mangler to get correct info out of aticonfig
+       if("CoreTemperature" == $attribute)
+       {
+                       $info = shell_exec("aticonfig --pplib-cmd \"get temperature 0\" 2>&1");
+                       if(($pos = strpos($info, "thermal")) > 0)
+                       {
+                               $ati_info = substr($info, strpos($info, "is") + 3);
+                               $ati_info = substr($ati_info, 0, strpos($ati_info, "\n"));
+                               $ati_info = trim(substr($ati_info, 0, strrpos($ati_info, ".")));
+                       }
+       }
+       elseif("Stock3DFrequencies" == $attribute)
+       {
+                       $info = shell_exec("aticonfig --pplib-cmd \"get clock\" 2>&1");
+                       if(($pos = strpos($info, "Engine")) > 0)
+                       {
+                               $core_info = substr($info, strpos($info, "-") + 2);
+                               $core_info = substr($core_info, 0, strpos($core_info, " "));
+                               $mem_info = substr($info, strpos($info, "Memory Clock"));
+                               $mem_info = substr($mem_info, strpos($mem_info, "-") + 2);
+                               $mem_info = trim(substr($mem_info, 0, strpos($mem_info, " ")));
+                               $ati_info = $core_info . "," . $mem_info;
+                       }
+       }
+       elseif("Current3DFrequencies" == $attribute)
+       {
+                       $info = shell_exec("aticonfig --pplib-cmd \"get activity\" 2>&1");
+                       if(($pos = strpos($info, "Activity")) > 0)
+                       {
+                               $core_info = substr($info, strpos($info, "Core Clock:") + 12);
+                               $core_info = substr($core_info, 0, strpos($core_info, "\n"));
+                               $core_info = trim(substr($core_info, 0, strrpos($core_info, "MHZ")));
+                               $mem_info = substr($info, strpos($info, "Memory Clock:") + 14);
+                               $mem_info = substr($mem_info, 0, strpos($mem_info, "\n"));
+                               $mem_info = trim(substr($mem_info, 0, strrpos($mem_info, "MHZ")));
+                               $ati_info = $core_info . "," . $mem_info;
+                       }
+       }
+
+       return $ati_info;
+}

 ?>
I now get my 2D clocks reported in system-info:
[uncle_fungus@Gecko phoronix-test-suite]$ ./phoronix-test-suite system-info

======================================
Phoronix Test Suite v0.6.0 (TRONDHEIM)
System Information
======================================

Hardware:
Processor: Intel Core 2 Quad CPU Q6600 @ 2.39GHz (Total Cores: 4), Motherboard: Unknown, Chipset: Intel 82G33/G31/P35/P31, System Memory: 7999MB, Disk Space: 10GB, Graphics: ATI Radeon HD 3870 (300/1126MHz), Screen Resolution: 3360x1050

Software:
OS: MandrivaLinux 2008.1, Kernel: 2.6.24.4-server-1mnb (x86_64), X.Org Server: 1.4.0.90, OpenGL: 2.1.7412 (fglrx), Compiler: GCC 4.2.3
GPU temp from sensors (not lm_sensors )
[uncle_fungus@Gecko phoronix-test-suite]$ MONITOR=all ./phoronix-test-suite sensors

====================================
Current Sensor Readings:

GPU Thermal Monitor: 44 C
CPU Thermal Monitor: 40.0 C
System Thermal Monitor: 37.0 C
CPU Voltage Monitor: 1.13 Volts
====================================